If they were intended to only be used as is in the squad role, then no, but having them would make it a lot easier for the Commanding Officer to retask to a Detachment Commander role in charge of dozens of personnel if not more.
That's fair. Yeah I could definitely see an HQ -insert divisional word- for a larger force. That makes sense. In vision at the moment is that while an HQ -unit- is absolutely a thing on a higher organizational level, it's not something that would always be in place, at least in any functional role. The
plan exists for when they need it but by and large, these forces are going to be almost by their nature more fluid and independent.
A vast majority of the time, these Marines are going to be operating on their own / with their ships or local areas whatever they made be doing. A good amount of time, there won't be dozens of personnel. Surely there will be some higher level officers who coordinate on the grander scale, at which point the permanent HQ totally makes sense, but I don't think there would be much in way of a middle command until such time as it's necessary to have one.
Actually, when we see them, they pretty much do work exactly like they do IRL, it's just that the show suffers with Main Characters Do Everything, so with the exception of O'Brien and Odo, the enlisted roles get overtaken by the equivalent main character (Chief Engineer, Security Chief etc).
Kind of? We very rarely see Enlisted at all, and we know Ensigns do a ton of what would otherwise be NCO work and there really doesn't seem to any actual rhyme or reason to if an NCO or Officer is doing the job. In an absolutely strict command aspect it may matter... but Starfleet has never really been shown to be all that rigid.
That's why I tend to observe that in Starfleet, the distinction between NCO and Officer just is not the same as it is in modern militaries. They use similar terminology and a very rough version of the organizational structure, but they really aren't quite the same thing.
The key to remember is that "Starfleet isn't a military". It
is in function, but within their organizational culture, they aren't. It's just not going to work the same way as a full-fledged military would.
No, Officers are for the most part generalists (even the doctors are to a degree), enlisted personnel are trained in a particular area and with the exception of O'Brien due to his long experience, struggle to adapt to working outside that (seen most clearly with the engineering team in Starship Down (DS9)
Those are basically the two examples. There's an Engineering team that wasn't good at ground combat, and there's O'Brian who is good at everything and has served in multiple roles (including Chief Tactical Officer...)
Although I don't necessarily think you are
wrong, but I think we get to a similar conclusion from different directions. Yeah, Enlisted are trained to do a thing. Officers go to the Academy, where they get a more universalist training. By that virtue, yeah an officer/Academy Graduate is generally going to be more adaptable than a someone who just enlisted into Starfleet.
Judging by O'Brian, and the general outlook of Starfleet, rank/status doesn't really matter as much as merit and ability do. By and large, up until that Commander level (that's been established as the "jump" into true Command), I really don't think Officer/NCO actually matters in any meaningful capacity. If Joe enlists in Starfleet and gets trained as a security officer, but it turns out that Joe is absolutely amazing at Stellar Cartography... Starfleet is not the type of organization to say "No. You're enlisted. Go do security stuff." They'll say "Welcome to Stellar Cartography."
NCO's will probably just be
more likely to be specialized into a particular role.
Not sure how I feel about Chiefs jumping all the way to Commander, but I could see them skipping at least Ensign and maybe JG as they're essentially going from "shift commander" to "department head" so at least Lieutenant would be reasonable.
This is Star Trek, where in a reality, Kirk jumped from
Cadet to
Captain.
Rank in Starfleet is not necessarily a completely linear path. It usually is. But i'm not sure there is any actual regulation that one must actually proceed through all the ranks to get somewhere.
I would maybe add a caveat that a Chief jumping to Commander may have some extra steps, probably including some kind of proof of equivalent Academy education or relevant experience. In the end, Starfleet is way more concerned about ability than remaining rigidly within a rank structure.
I'm still mostly convinced that NCO ranks in Starfleet are somewhat irrelevant and by and large essentially mirror 1:1 officer ranks... ish anyway. "Crewman" would be below Ensign, but I think at some point, the ranks are mostly interchangeable.
Security (aka weapons specialist) and medical are pretty much going to be required in any combat situation, and operations/engineers would likely focus on demolitions and setting up base-camps and the like, which is a massive deficiency in canon vis-a-vis extended operations IMO.
Yes... which is why I think these "Marines" are generalists just like much of the rest of Starfleet. They'll have medical training. If specialist medic is required, they'll get one from their local pool of Starfleet personnel.
These Marines i'm speaking of are something more akin to ENT Maco's / More Specialized Ship Security / SWAT Team. These are people who are combat focused employed by an organization that touts itself as not being a military. When there is a situation that would require a more specialized officer, they have access to them. They just won't necessarily be full-time Marines.
Agreed on the first point, in fact that's basically how it works in canon, though TrekLit kinda confused the issue with the mini-series.
Going really into the weeds of canon and sifting through even the smallest of mentions, there ARE two seemingly separate divisions, "Starfleet Engineering" and "Starfleet Corps of Engineers". I just headcanon the Corps of Engineers to be combat engineers because... that's usually what a Corps of Engineers is?
I know my idea for the command flip-flop is a bit unorthodox, but this whole exercise to make this as within Star Trek as possible. Having a full fledged ground combat military force just doesn't really work with Star Trek. Going with the idea that "Starfleet isn't a military", but WILL BE when it needs to be... I think the idea of a more Civilian-Oriented Command during peacetime, with more combat-ready departments ready to go and taking over the overall command at such time as Starfleet is now
actually a military.
That would mostly apply to the high echelons of command though, it's not like a ship is going to have it's Captain removed for the Military Captain. It's more on the higher end of command, when Starfleet is focused on Exploration stuff, have the Explorers in command. When it's focused on military stuff, have the Soldiers in command.