With that, then, Kevin, the Enterprise crew will have to be subjected to considerable danger...thus making the next Trek film likely another heavy action-adventure film...much to the chagrin of the Roddenberry dogmatists. (A term I am not using insultingly...but for brevity...to describe those who want to see a TV series episode type story made for the big screen that involves more exploration and cerebralism than a largely action plot.)
Although, there are other avenues that can be approached aside from action/adventure. The crew could be stricken with a major illness over or on an alien world. A technical catastrophe (similar to one that struck the Enterprise D when they hit a quantum string in one TNG episode) that also causes grievous injury to many of the crew, and disables the ship...a sort of "ship in distress in the far reaches of space with no help to be found" film...a ship disaster film.
In any case, the point I'm making is that something has to happen that strikes a chord with the audience to care about the fate film's protagonists...in this case, the stalwart crew of the Enterprise.
One of the most popular Trek films largely dealt with a threat to Earth, because the audience cares about our homeworld. (Witness The Voyage Home). Star Trek TMP could've worked in this fashion if the characters weren't (supposedly, from most others' point of view) so wooden, and the story not so sterile. Wrath of Khan worked because the Enterprise crew were in grave danger from a madman. Trek III worked because the Enterprise (a character unto itself) met its fate. Trek V? Well...let's just say "Thank God for VI!" Trek VI worked as a murder mystery and a light action film.
Generations worked only because it was the first TNG film. There wasn't really that much to care about in Generations. To most who are well versed in Trek, this really felt more like an overblown episode with the heavies feeling more like afterthoughts and guest-stars as opposed to genuine threats.
First Contact worked by bringing back the Federation's most popular nemesis (The Borg), and again putting Earth (there's that lovely blue planet of ours) in grave peril.
Insurrection again didn't work all that well because the planet was alien...someplace the general audience didn't really care about. The threat to the Enterprise crew (F. Murray Abraham's considerable acting skills notwithstanding) was just not compelling. There wasn't much to grab the audience with...not even the theme of forced relocation.
Nemesis....well, despite my love for this movie, I do see the flaws. Lots of Scimitar sized plot holes (although my imagination and experience with Trek allows me to deal with them satisfactorily), seemingly cookie cutter characterizations, and a gigantic space battle where shields were "down to 10 percent" and the "warp core was offline" for the umpteenth time in Trek film history. Although Earth was a potentially threatened party, much of the Trek audience, and pretty much the general audience just didn't give a frak.
So basically, while the first new Trek film was massively popular for its radical turn it took with the action, humor, and overall storytelling, a second new film will have to engage the audience on a level where they really do care about what's going on...and in an exploratory piece, or an alien world piece, that will have to involve some kind of major adversity to something we care about...namely the crew of the Enterprise.
Just my two quatloos and three strips of latinum.
BTW, I say "Bringon the Klingons!"