The adventure is just beginning...
I've done a chronological rewatch before. And thought not intentional, there is a fascinating subtext regarding the role of the Federation that is revealed when watching it like that. The Federation goes through cycles of exploration->growth->retrenchment->militarization->war->peace/disarmament->exploration. The shows we have seen broadly represent 5 eras (with a 6th forming, in the 32nd century).
The First Era - The Birth of the Federation, the first Age of Expansion and start of "modern" interstellar politics
2063 - Human's stage their first Warp I flight, followed by Human-Vulcan first contact. In the months and years that follow, Vulcan Central Command becomes extremely concerned with the Human race. Going from a global nuclear conflict to warp capable in 10 years has uncanny parallels to how the people who would become the Romulans left Vulcan 2000 years before. Concerned that Humanity could become a dangers to the region if left unchecked, they begin a mutli-decade partnership with humanity that both helps them rebuild from World War III and advance some technology, but also significantly slow them down in their ability to rapidly get to other star systems.
2151 - Over Vulcan protestations, the NX-01 launches and Earth gains the ability to engage in interstellar affairs on its own, albeit it still significantly technologically inferior to most of its neighbors. Over the next several years, Earth becomes the mediator between various local civilizations that have been, at best, cool to each other and sometimes in open conflict. Crucially, Earth begins exploratory mission to uncharted sectors mostly into what will later be known as the Beta Quadrant. For many decades, or even longer most of the local powers have kept their ships very close to their home systems for defensive purposes, leading to interstellar space being rather lawless. Marauding ships aren't uncommon.
In general however, local space is divided and relatively weak. The Romulan Star Empire is spoken of distantly and far away. The Klingon Empire is feared, but despite local space's proximity to the Klingon Homeworld, Klingon expansionist interests seem to like elsewhere ("eastward" deeper into the Beta Quadrant.
The situation changes in 2155. The Romulan Star Empire grows increasingly concerned that Earth is uniting the fractious systems in its region over a series of regional security incidents. It tries to provoke a Vulcan-Andorian War that would destabilize the region. When that attempts fails (rather spectacularly), it launches a series of covert attacks using drone ships to provoke another conflict. It not only fails but manages to unintentionally unite the major space fairing powers of local space - Vulcan, Andor, Earth and Tellar - like never before into what soon would be called "the Coalition of Planets". For the first time in at least living memory, there is an emerging order that could stabilize the security of local space (resolve the marauding alien problem, provide for collective defense) and provide for a standing means of peaceful resolution of disputes.
The biggest event for the next 150 years though would be the Augment Virus crisis. The Klingon Empire messes with genetic engineering based on 20th century Earth enhanced humans and ends up accidentally warping their genome to remove Klingon traits and change Klingon cognition and behavior. While the NX-01 resolves this crisis, the aftermath destabilizes the Klingon Empire, that seemingly fractures into warring houses and becomes insular for the next century, effectively removing them from the map.
2056-2060 - The Earth-Romulan War begins as the Romulan Star Empire decides to directly address the stabilizing security regieme that has this upstart Earth at its center. The Coalition of Planets evidently did not become involved until 2160, when at the Battle of Cheron, the Romulan Empire was decisively defeated by the intervention of the other Coalition members. The costs of the war were so great that the Romulan Empire was apparently marginalized as regional power for the next 100 years.
2161 - The United Federation of Planets founded with the core 4 of the Coalition of Planets as its founding members. It becomes a more formal interstellar government the the loose arrangement of the Coalition.
2062-2255 -
The Federation's first Age of Expansion begins.
With The Klingon Empire entirely destabilized and in the midst of a Civil War, and the Romulan Star Empire in an isolationist phase, the Federation begins a nearly 90 year period of growth and expansion where it builds up institutions, harmonizes technology and shipbuilding, and grows to include dozens of worlds who find the mutual protection and trade agreements offered by the Federation beneficial. Earth Starfleet becomes the basis of Federation Starfleet whose core mission is to seek out new worlds and civilizations. With the Klingons and Romulans indisposed, Starfleet acts a principally exploratory organization. It has a defense function, but it is secondary to its core mission of exploring the galaxy and growing the Federation. By the end of this period, the Federation we know has emerged, though it likely only counts dozens of members (let's say 60), mostly in the Beta Quadrant.
The Second Era - The Klingon-Federation Wars, the end of expansion and the militarization of Starfleet
2256 - The Klingon Empire remerges after a century of intercene conflict under T'Kuvma. Some Klingons have taken a wildly new form - perhaps a result of try to use genetic engineering to undo the cosmetic and psychological legacy of the Klingon Augment Virus. The Battle of the Binary Stars occurs, leading to the Federation-Klingon War of 2256-2257. Starfleet, focused one exploration and growth, is badly overmatched by the Klingons and loses 1/3rd of its fleet and many border worlds. By 2257, the existence of the Federation is threatened as the Klingons are within striking distance of the core economic, military and industrial powers of the Federation. The war ends when Discovery and Section 31 manipulate the situation to get L'Rell to become Chancellor, who ends the war.
2258 - L'Rell continues the process of uniting the Klingon Empire into a single, cohesive political and military entity as the fractious nature of the Federation-Klingon War exposed how fragile T'Kuvma's attempts at unification were.
2260s:
In the years after the Federation-Klingon War, Starfleet begins a rapid and expansive militarization initiative that lasts much of the next 30 years, in direct response to the near-loss of the Federation-Klingon War of 2256-2257. The Constitution-class becomes the basis for an expanded starfleet based on variants of its cruiser configuration. While initially this means simply building many Constitution-class ships itself, in the mid-2260s and into the 2270s the came to include the Miranda class and other variants (some of which would serve for the next 110 years). The original Constitution-class design, based on 2240s technology, would be refitted several times in the 2050s and early 2060s, before settling on a unified single refit conflguration in the late 2260s that was carried over to the derivative classes.
During this period, Kirk engaged in his legendary five year mission, most of it in which took place in what would later be known as the Alpha Quadrant, which in the 2260s was largely unexplored (security concerns with the Romulans and Klingons required the a focus on the Beta Quadrant in prior decades). But his mission of exploration was largely an exception to a Starfleet that was transitioning to a more militarized nature in response to the Klingon threat.
Throughout the 2260s the Federation encountered the Klingon Empire much more frequently. The Klingon Empire had seemingly fully stabilized by the middle of the decade for the first time in over a century. The Klingon body type of the prior decade had totally disappeared. Another war with the Federation was adverted through the timely intervention of the Organians in 2267. The Treaty of Organia provided the basis for stable, but cool relatons for the next 25 years and prevented another Klingon-Federation War. Starfleet still continued its growth, modernization and militarization plans as the near miss of another war, plus the reemergence of the Romulan Star Empire for the first time in over a century (and their brief alliance with the Klingons) showed that the security situation was at great risk of rapidly deteriorating.
2270s:
The federation continued its ship building program, but this was mostly a quiet decade. It was typified by a transition away from Starfleet operational practices of the 2250s and 2260s into an operating norm that would be carried through the mid 24th century. Refit-Constitution class and Mirandia-class (and variants, such as Soyuz) were rapidly and inexpensively built out. The Federation still kept many of it's ships on the boarder, but Kirk engaged in at least 1 (and probably 2) more five year missions of exploration. Also notably during this period, the Klingons began to fully undo the legacy of the augment virus and got ever closer to their pre-virus look and personality.
Also in this decade the Federation began "the Great Experiment", a series of technologies, including transwarp drive, that would be implemented in the Excelsior class. The Excelsior was planned to be the basis for a new generation (probably the 5th) of Federation Starships, to replace the Constitution-based ships of the prior 30 years (4th generation?) as the foundation of Federation starship design and technologies. The Excelsior, it was imagined, would be the ship class that would carry Starfleet into the 24th century once the Constitution-refits and their variants were phased out.
Towards the end of this period the "militarization of Starfleet", again, the long term response to the Klingon War, culminated in the adoption of the red military-style uniforms.
2280s: The political situation while stable, risked a rapid unwinding due to the Genesis program. While the Federation's intentions were peaceful, the Klingons saw it in the context of the Federation's perceived (and actual) militarization as a superweapon. Only the failure of the technology prevented a worse political situation. Klingons nearly fully-undo the damage the augment virus did to them, but culturally they have a long road ahead. Klingons of this era are not yet returned to beliefs in honor and tradition and still act very human.
2293: Praxis explodes. The Klingon Empire, faced with an enormous environmental catastrophe that could potentially destabilize the Empire again, reach a peaceful settlement of all disputes with the Federation at the Khitomer conference. The Klingon-Federation Cold War ends and the Federation abandons its military build up as it dismantles bases and downsizes its militarized starships. The Klingon Empire and Federation have cordial relations, but are not yet allies.
The Third Era - The Long Peace and the Federation's Second Age of Expansion.
2294 - 2365:
With the threat of an existential war with the Klingons now gone for good, the next 70 years of history see the Federation and Starfleet vastly reducing its military focus, resuming its exploratory focus and rapid expansion.
With the security situation rapidly improving, the Federation shifts back to a policy of exploration, principally of the Alpha Quadrant.
In the first decade of the peace, 2294-2300, the Constitution-refit class is rapidly retired, despite some ships being relatively young. Many Miranda class ships remain in service. The Excelsior (and some Excelsior refit) classes, minus Transwarp drive, enter service and become the backbone of the Federation Starfleet for the next 50+ years.
The most notable security incident in the first decade of the Peace was the Tomed Incident, which saw a brief, but significant military encounter between the Federation and Romulans for the first time ever (unless you include the Earth-Romulan war which predated the Federation). The outcome of the Tomed Incident drove the Romulans into a 50+ year period of isolation where they evidently focused on other matters than relations with the Federation and Kligons (perhaps their eastward borders?). Notabely, the Tomed Incident did not disturb the long peace.
As the Long Peace period bore on, the Federation explored and expanded ever further into the Alpha Quadrant, until it came up against the borders of five different significant powers that prevented further expansion.
The first was the Tholian Assembly. The Tholians and Federation had encounters in the mid 23rd century, and perhaps earlier, but the scope of their vast domain became clear only in the 24th century. However relations never boiled over into a major military conflict.
The Ferengi were objects of rumor for much of the 2340s, 2350s and early 2360s. Encounters were few and generally hostile, but the nature of the Ferengi political system and the security threat it posed (or if they were just independent operators) wasn't clear. While for a time it was believed the Ferengi could be a major military power akin to the Klingons, that was later found not to be the case and hostile encounters mostly due to enterprising rogue ships. The Ferengi Mauarder proved very advanced for the 2350s, but it's military power turned out to be somewhat overstated.
The Federation encountered the Tzenkethi in in the middle of the 24th century and fought a brief war. While the Tzenkethi were evidently no match for the Federation and the conflict wasn't a large one, it proved a formative experience for some officers and blocked the Federation from further expansion into that region of space.
Most significantly to the future of the Federation and Alpha Quadrant, was the first contact between the Federation and Cardassian Empire. The Cardassians were the nearest Alpha Quadrant great power to the core of the Federation and the most significant military power by far, nearly rivaling the Klingons. And unlike the Klingons, they were engaged in an active period of expansion deeper into the Alpha Quadrant and near Federation space. This lead to the Federation-Cardassian border wars of the 2250s. While in the context of past (and future) military conflicts, they were not large engagements, they were bitter ones and proved to be the most significant military episode during the long peace, and the only principle military experience for an entire generation of Starfleet officers. Keeping the peace with the Cardassians - likely to avoid a return to a militarization policy - was a core focus of the Federation, and of Starfleet for much of the 2350s and 2360. In foreign policy terms, the Federation was being a "status quo" power (in that, the status quo benefited it greatly) and accomodated the needs of the lesser, upstart rival in order to prevent an escalation of military matters.
But even the Cardassian Border wars did not change that the long peace was generally extremely stable and peaceful for everyone in local space. Klingon and Federation relations continued to improve, to the point that, after the Enterprise-C's relief to Romulan attack on Narendra III, the Federation and Klingons entered a formal security and alliance (the Khitomer Accords), one furthered by the Romulan attack on Khitomer itself (symbolic) 18 months later. Klingon-Federation relations proved so good that humans and klingons started to have interpersonal relations, marry and even adopt of children was facilitated.
Within Starfleet, several things happened during the long peace that typify it.
The Federation began a successor program to the Excelsior class, that it thought would prove to be the base-model starship for the second half of the 24th century. The Ambassador-class, however, proved to be merely a half step. It was more advanced and capable than the Excelsior, but was not as much a leap forward as the Excelsior was from the Constitution. Few were built, while Excelsiors continued to be upgraded and produced. Furthermore Miranda-class ships continued to be modified and improved, likely owing to a vast surplus of components from the military build up of the 2260s-2290s, deep into the 24th century. With the Constitution-refit long out of service and the Ambassador class leading to no variants and short production, the Excelsior class and Miranda class proved to "the face" of Starfleet for the first half of the 24th century.
The leap forward Starfleet was seeking would be found in the Galaxy class of the 2260. However the Galaxy-class, the most ambitions, integrated technology and starship program yet attempted was an endpoint that required significant development on other types of starships first. Before the first Galaxy class was built, nacelle designs, interior designs, components, hull parts were all developed and implemented on smaller, less ambitious but meaningful ship classes, such as the New Orleans class, the Freedom class and the Niagara class. While none of these implimented the full suite of technologies the Galaxy class would, and where very much a half-step between Ambassador/later Excelsiors and Galaxy, they were an essential part of development and it was thought would make up the "face" of Starfleet in the 2nd half of the 24th century, alongside the Galaxy class. Unfortunately that provided not to be the case for a variety of reasons and once the Galaxy (and its derivative Nebula) entered service, no more of those "half steps" were built. However, likely the Excelsior-derivitives and the Constitution-refit derivitives before them, they were all united by a common window, hull, nacelle and similar saucer design. Ultimately, however, it wouldn't prove nearly as enduring as its predecessors.
The Galaxy class represented not just a technological achievement for the Federation and STarfleet, but also a statement of its philosophy at that point in time. With the long peace, besides Cardassian border skirmishes, seemingly continuing without end, and the space the Federation could explore and expand into ever further away, what was needed was ships that could be self sustaining for far longer than any class built previously. With warp speed having "just" doubled in the past 100 years, 5 year missions wouldn't be enough before long. So in the late 2350s and early 2360s Starfleet began the controversial policy of allowing officers to include their families on their ships, with the Galaxy and Nebula class being built around this philosophy.
This was fundamentally a statement of belief that the military conflicts that were so formative to the Federation in the 23rd century were now permanently behind them.
2364 - The Enterprise-D, the most advanced of the Galaxy class starships, is launched on a mission of deep space exploraiton. It spends its first few months in the northern periphery of the Alpha Quadrant, near the unclear (at that time) borders of Ferengi space (and has several encounters with them), however it soon spend much of its time along the periphery of the Beta Quadrant, beyond Romulan and Klingon space. This columinates with the return of the Romulan Empire to interstellar affairs as both agree to investigate the destruction of several colonies along their borders. The Romulan D'deridex class, twice the size and power of a Galaxy-class starship, comes as a surprise.
(end of Part 1)