Star Trek is a different beast altogether. Kirk, Spock, McCoy are the iconic characters of Star Trek. As fans we may like all the others too but they all stand in the shadows of those original characters.
I think if you can't get away from having to have Kirk, Spock, McCoy, then Trek should not continue.
There's a HUGE universe in Trek, but to keep going back to the well and endlessly recast/remake/reimagine/recycle those three like they are comic book icons is pathetically uncreative.
Obviously it takes a lot of work to come up with new characters that can match the popularity of the originals, but darn it, why can't writers exert a little effort??? Someone had to conceive of Kirk, Spock, and McCoy in the first place. It didn't just spawn out of the ether. You just get cracking and come up with something new.
The problem, at least as far as Paramount is concerned, is, as of Star Trek '09 Kirk and Spock are profitable. So, if they went down a non-established character route, then they would have to "dumb down" Star Trek even more to bring in an audience. This includes casting the likes of Vin Diesel, Paul Walker, Seth Rogen, etc., just to get asses in the seats. And I, for one, do NOT want to see a stoner Star Trek movie (not to say, I don't enjoy stoner movies, Pineapple Express is one of my faves).
Again, I'm not saying that Star Trek would necessarily have to become a stoner movie, but in order to catch the attention of some of the bigger stars that would have to be attracted to a role in such a movie, Trek would need to be dumbed down even more (I use dumb down in the sense of all the complainers. I happen to enjoy Trek '09 very much). I'm not even sure how the marketing for such a movie would go.
"From the producers who brought you Star Trek and Your Highness, comes a Star Trek spinoff about a Federation garbage scow! Suit up as you join Captain Randy Randerson and the crew of the U.S.S. Entrepreneur
as they clean up the galaxy! Of alien scum!
Dwayne Johnson as Captain Randy Randerson
Owen Wilson as First Officer Chet Manly
Vin Diesel as Lt. Commander Duncan Cox
Megan Fox as Dr. Eleanor Jorgenstern
Zach Galifianakis as Chief of Security Raoul Beardly
and Shia LaBeouf as Ensign Michael Hunt
in a Jerry Bruckheimer production of a Michael Bay film.
STAR TREK: TAKING OUT THE TRASH. Hey, it's a shitty job, but SOMEBODY'S got to do it! Coming Summer 2016!"