This is an interesting question, framed up in a different way than the typical "what's your favorite movie" poll.
But, I think I get what the OP is looking for. What movie seemed to cover the most ground in terms of characters, theme, physical distance, etc? That's a different question from "what movie did you like the most?" and I like that approach. So, I will answer from that perspective...unbiased about how much I actually like the film.
Factors:
Characters: how much do we learn about the characters? How much do they endure / develop, etc?
Theme: where the themes thought provoking, grand on a human scale, and brain-ticklingly sci-fi?
Physical/Distance: did the loom and presentation of the film expand our appreciation for the Trek universe and the cosmos in general?
I will rate these on a 1-5 scale, with 5 being highest.
TMP:
Characters: 4 The arcs for Kirk and Spock respectively are excellent. This is one of the best Spock stories in the entire franchise. Excellent, contained character arcs here.
Theme: 3 Although derivative, the "universal search for meaning and purpose" is a strong theme, as is the theme of evolution to a higher plane by combining the better parts of two very different life forms.
P/D: 5 There has never been a Trek film as impressive as this in terms of physical scope and what this did for exploring the Trek universe. This film set the tone for all Treks that followed.
TOTAL: 12
TWOK:
Characters: 3 This is a powerful Kirk story- facing middle age, accountability for his past decisions (David, Khan, accepting the Admirailty, etc), and ultimately death. But there is really no development for the others of any significant value.
Theme: 2 great movie...but this film has a couple pretty simple themes: vengeance and the passage of time/changes in our lives as we grow older.
P/D: 4 I agree that this movie feels like it is "out there
" far removed on the frontier. We see new worlds, meet new characters, see a new starship, journey deep into a planetoid and into a spectacular nebula. Very cool.
TOTAL: 9
TSFS:
Characters: 4 An excellent follow-up to TWOK, we see all the main characters in the spotlight in this one. For the first time, the true camaraderie and family between these people is absolutely clear and they sacrifice everything for that.
Theme: 2 Again, pretty simple here- with themes of friendship and sacrifice. Very well-executed, but simple.
P/D: 5 this comes close to TMP with regard to the impact to The Trek universe (BoP, Excelsior, Oberth, Spacedock). This is also the best depiction of the Klingons in the franchise in my opinion (close to Day of the Dove and Errand of Mercy). Also had a feel of major galactic impacts with the Genesis repercussions.
TOTAL: 11
TVH
Characters: 2 Not too much here. Lots of fun, not a lot of substance. Some warm moments as Spock rediscovers himself...but that's about it.
Theme: 1 Again, pretty mundane and straight-forward here. A nice cautionary tale regarding the impact our carelessness has on the environment and our future.
P/D: 1 Nada here. A happy little trip between the two most popular planets in Star Trek. Time travel is fun...but it just didn't add scope or a sense of wonder to this film.
TOTAL: 4
TFF
Characters: 5 I thought this was one of the very best films in the franchise regarding exploration of the main characters, their motivations, histories, and relationships. Introduction of Sybok adds an interesting insight on Spock's history and motivations.
Theme: 4 there's some heavy stuff here, despite the questionable execution. We get into the nature of God, the impact of false idols, and the role that pain and tragedy plays in our lives.
P/D: 3 The locations and the journey the crew takes are impressive and noteworthy, but the FX and lack of execution take away from a film that could have easily been a "5"
TOTAL: 12
TUC
Characters: 4 Interesting and risky arcs for the characters facing the ends of their careers, questioning their relevance, and battling their prejudices. Lots of classic and poignant exchanges between Kirk &McCoy and Kirk & Spock.
Themes: 2 Fear of change and prejudice are powerful but common themes. TUC didn't really handle these in an interesting or thought-provoking way.
P/D: 2 Some cool stuff here is really limited by budget and rushed production. In theory, this should have been a great intergalactic story, but it just didn't feel that way.
TOTAL: 8
GEN:
Characters: 3 nice arc here for Picard, and Data is fleshed out a bit more with the emotion chip debacle...but this is pretty run-of-the-mill otherwise.
Themes: 5 I love the themes of this movie- the very nature of our mortality, the role death plays in the value of our existence, and our inability to avoid reality. I've always thought this was powerful.
P/D: 4 much like WOK, this movie really feels like the crew is out on the edge of explored space, far beyond Starfleet's easy reach. The Nexus is a flawed but cool scifi concept. We have exploding stars, Klingons, and lots of other cool treats on top of that.
TOTAL: 12
FC:
Characters: 3 Awesome character stuff for Picard here, facing the demons of his past and going a little too far in Terms of his vengeance etc...but very little else.
Themes: 1 I'm actually not sure what FC's theme was.
P/D: 2 Some fairly impressive stuff here with the Enterprise-E, the grandness and evil of The Borg, and the history of the first Warp Flight. But, otherwise, pretty limited.
INS:
Characters: 1 iNS offers very little character development. Picard gets a temporary love interest, Worf gets zits, and Data can serve as an emergency floatation device. Hmmmm.
Themes: 1 ummm...again, not sure.
P/D: 2 interesting new planet and region of space deep on the frontier, lots of new alien species, and some cool ships...but otherwise this is very contained and limited in scope.
TOTAL: 4
NEM:
Characters: 4 Good development for Picard and Data most definitely, with Riker and Troi also moving on in their personal and professional lives.
Themes: 3 some interesting "nature vs nurture" themes here, exploring the value of how striving to be more than the sum of our parts is critical to who we are.
P/D: 4 alien worlds, Romulus and Remus, the Basen Rift, and tons of new ships, plus looming peace/war with the Romulans give this a really grand sense of scale.
TOTAL: 11