...No Starfleet yet. There are two predecessors instead, the purely exploration-oriented United Earth Space Probe Agency and the totally defense-oriented United Earthcorps Command.
...A less Star Trek-looking ship...Keep the submarine interior idea.
...Have the ship be a joint venture between UESPA and Earthcorps (a heavily-armed exploration vessel). Have the crew composed of UESPA mission specialists and Earthcorps officers & enlisted who don't always see eye-to-eye on aspects of their mission.
...No alien crewmembers aboard the ship...
...Ditch photonic torpedoes and phase cannons & pistols...
...With the exception of T'Pol as the aforementioned Number One and Phlox as a Human, the rest of the characters remain mostly the same. Mayweather is a stronger presence on the show as a lieutenant with "Kirk-like tendencies." Sato's role is also beefed up as someone with experience dealing with different alien cultures. Reed is a major from Earthcorps.
Ringship.
A lot more trouble with the technology.
A more NASA style approach to the whole crew and ship.
...
No visual communication with many races.
No Klingons.
No Ferengi.
No Borg.
More language barrier problems.
More alien aliens and worlds.
More wonders, bizarre stuff and excitement. STRANGE NEW WORLDS, for crying out loud!
No transporters.
No phasers.
No photon torpedoes.
Nuclear weapons.
No Scott Bakula.
No T'Pol and especially no Vulcans are backstabbing racist motherfucking assholes plot.
No Temporal Cold War shit.
...
That's pretty much what I've been trying for in my fanfic. The Declaration class Enterprise, a modified ringship design, is a warship built by the United Earth Military Authority, modified for deep space exploration. The entirely human crew is a mix of UESPA, UEMA, and civilian specialists. The ship is armed with plasma cannon and nuclear tipped torpedoes. No shields, no transporters.
Captain Archer actually has some experience with exploration and diplomacy, and isn't just some whiny biatch who got the job 'cos his daddy built the engines. The XO, Maria Hernandez, is career military and doesn't approve of the more laid back approach shown by the UESPA people. Trip Tucker didn't learn to fix warp drives by working as a mechanic on fishing boat engines, and despite his home spun ways has been educated at Cambridge in sub space field dynamics. And the chief scientist is a hot babe in a ridiculously tight catsuit. Well, I didn't want to mess around with the formula too much.
