The nature of a thread like this is based on fans like ourselves in the here-and-now, expressing their sentiments while agreeing that hindsight is 20-20.
Some things said above I agree with, others, no-so-much.
I did not mind the theme music or cast of characters at all. In fact, I really liked them. I could even look beyond the naming of the hero-ship Enterprise; not a biggie.
Here are things I was concerned about. Warning: many of these sentiments have been expressed before...
The show's look, and how it presented and used the Enterprise in situations, made it look too TNG-ish, like Sisko's Defiant without shields or the Enterprise-D with some missing size and technology. Very controversial from the start, and it conflicted with the idea that the NX-class starship was a brand-new thing, and the Enterprise being the prototype. A delicate, first-time-ever ship like that doesn't just woosh its way to escape peril just in the nick of time like the Millennium Falcon.
They needed to start out with a story that did not involve the Klingons. I would have favored "First Flight", to better establish the characters' histories and why the Enterprise came to be. And we needed more stories like this.
I agree on the Temporal Cold War. How Archer was able to combat time-travelers so easily made no sense. It all seemed so contrived. It also delayed the telling of the Romulan War story. That's the important story arc.
While I really enjoyed the basic makeup of the cast, and the premise of NX-01 being the first "warp five engine" starship from Earth to make it "out there", I had a basic problem with the characters stumbling around and making fools of themselves and the general atmosphere seemed a bit wooden. (Much like SPACE: 1999) This seemed to be in direct contrast to STARGATE SG-1, another space-travel show with Earthling characters daring to take the plunge and do things never done before. Only Jack O'Neill and Cam Mitchell and their crew had a lot more fun and that show's sense of humor made it easier to enjoy the adventure. Tracing a problem back to TNG, ENT seemed to lack a McCoy/Pulaski-like smartass, an essential ingredient in TOS and SG-1. "And then he gave me something that reminded me of the Seventies" ("Jolinar's Memories") was the kind of thing that made SG-1 fun to watch by both making the characters more human and making how they articulated their situation much more interesting.
What ENT, and indeed, all of Bermanian TREK, was missing was an overall creative agenda. Where was this show taking us? I'm not suggesting story arcs, even though these would be an interesting possibility. I'm talking about what the show was trying to say. I loved how we were presented with Archer and Trip was the pioneers who literally built the Warp 5 engine and the NX-class from the ground up, and how they represent the spearhead of Earth's ambition to burst out into deep space, with the Vulcans cautioning they weren't ready. But that's it? Surely there needed to be more about what this meant for the human race and the characters directly.
Berman and company did have some neat ideas on how to distinguish the NX-01 Enterprise from other Enterprises we had seen before. I love the set designs. They did a beautiful job showing that. But they really stumbled when they showed the Enterprise firing "photonic torpedoes", possibly the silliest double-talk ever in TREK. TOS virtually handed the answer to them on a silver platter in "Balance of Terror":
SPOCK
Referring to the map on your screens, you will note beyond the moving position of our vessel, a line of Earth outpost stations. Constructed on asteroids, they monitor the Neutral Zone established by treaty after the Earth-Romulan conflict a century ago...
As you may recall from your histories, this conflict was fought, by our standards today, with primitive atomic weapons and in primitive space vessels, which allowed no quarter, no captives. Nor was there even ship-to-ship visual communication.
Therefore, no human, Romulan, or ally has ever seen the other. Earth believes the Romulans to be warlike, cruel, treacherous, and only the Romulans know what they think of Earth. The treaty, set by sub-space radio, established this Neutral Zone, entry into which by either side, would constitute an act of war. The treaty has been unbroken since that time.
So... what have we established here? Earth (and presumably the Romulans) had at least some starships, but they were "primitive" next to TOS. And Spock called it a "conflict", not an all-out war. They only had "primitive atomic weapons" and capacity was limited to "no quarter, no captives". Subspace radio existed, but was still primitive and apparently much less reliable. (No viso-phone calls to headquarters, please.) The Goldstiens' 1980 "Spaceflight Chronology" also offered a clue: those ships used crude lasers and fusion torpedoes. Berman & company started to get this right, making the Enterprise's first encounter with the Romulans be a minefield, but then they screwed up. "Balance of Terror" indirectly suggested that much of the conflict would have to be more like piracy or a proxy war, with third parties stumbling into committing acts of violence or perhaps acts of deadly terror/sabotage/espionage. No holo-ships or proto-Warbirds necessary, at least not from the get-go. (
XFozzboute did a better job, hindsight being 20-20, at
showing us what a more plausible Warbird could look like.)
Introducing the Transporter mechanism to the late 22nd century was a dicey move as well. It seemed like no time at all and people were saved by the skin of their teeth in split-second beam-ups. If the technology is supposedly still new, they should not be able to do that.
As mentioned before, I liked Russell Watson's/Diane Warren's "Where My Heart Will Take Me". I actually saw this as a positive development. I was disappointed when TREK episodes stopped opening with a "space, the final frontier..." narrative. I thought it was an important tradition in the franchise. DS9 and VOY seemed to ignore that, and I was glad to see it brought back in the form of a song. Having said that, I wish they had not re-mixed it with more instruments. It sounded better in the show's first year. If they wanted to do something new with it, they should've hired Sheryl Crow to re-do it.
I liked what was done with the Andorians, Vulcans and Tellarites. We needed to see more friendly (or potentially friendly) characters like Shran that could evolve into allies.
There were amazing contradictions in the show. They had Warp 5 engines, artificial gravity, an early transporter, a navigational deflector dish, and the beginnings of photon(ic) torpedoes and wanna-be phasers. Yet they were still tinkering around with forcefields and used cable-"grapplers" instead of tractor-beams. This is just me, but it makes no sense to design the ship with the catamaran-like assemblies and all the swoopy Akira-prise curves and then try to pass her off as an early starship. There is an alternative drawing of what the studio artists envisioned the NX-01 to possibly look like without the catamarans, and with a crude secondary hull. If you look at the
Starfleet Museum's artwork, there are sound ideas there, such as the Moskva, Gagarin, Hyperion and Lancaster. Any of these would've made a more interesting NX-01.
The only set I did not like on ENT was the engine room. It looked too much like someone steampunked the Enterprise-D's engine room.