I've been able to boil down my concept of "what is Star Trek?" to two words: ethical exploration.
I like this definition because it doesn't just convey the concept of "exploring ethically" (although that's a highly visible aspect of Star Trek) -- it's also about exploring our ethical beliefs. Star Trek at its best was never afraid to ask the big questions, and insisted that those questions are inevitable when you travel beyond the fields you know. The true explorer knows there'll be hard decisions to make about the right uses of advanced technological power, and welcomes such questions because facing them directly is how we grow.
The great thing about this -- if it's as emblematic of Star Trek as I think it is -- is that it's something new to the MMORPG world, but not so new that people would have a hard time getting into it. Most MMORPGs are about hitting each other with pointed sticks and taking the loser's stuff, but the better angels of our nature still exist. Isn't it about time someone offered a game that spoke to both sides of our humanity?
More specifically, it's time some smart developer made a MMORPG that rewards constructive play, rather than yet another game in a crowded marketplace of games that are only about destruction. Star Trek would seem to be tailor-made for this! Instead of killing other living things and seeing who can most rapidly collect the most stuff, Star Trek's ethos is cooperative and constructive -- go see what's out there, and share it with your friends.
Of course there are going to be bad guys in the galaxy who only understand force. Nothing in the Federation charter says you can't defend yourself when someone attacks you, so a Star Trek MMORPG need have no shortage of armed combat for those who are focused on that kind of thing. But a Star Trek Online is also a rare chance to offer something more, to communicate Star Trek's vision of ethical exploration. That doesn't just make for fun gameplay (who wouldn't want to figure out how to use the deflector array to open a gateway to fluidic space?); it's also a golden opportunity to tell truly compelling stories by occasionally asking players to make tough ethical choices.
The value of that last feature should not be dismissed. A major reason for the success of BioWare's single-player RPG Knights of the Old Republic was that the action in the game wasn't just action for its own sake -- your choices had ethical consequences. What you did affected your available choices later. It mattered. The lightsaber action was fun, but it was the ethical component of the gameplay that made KOTOR stand out.
Well, why should the Star Wars franchise have all the fun?
The ethical exploration that IMO is fundamental to the Star Trek license is just begging to be fully implemented in a MMORPG. Such a game has a chance to grab that part of the online gamer audience (of whom I'm one) that has had enough of mindless shoot-'em-ups and "casual players need not apply" loot raids and is ready for something that challenges their hearts and minds. I don't pretend to know exactly what percentage of the total online gamer population that is, but we're out here, we're not negligible, we're solvent, and we're ready to send our money to any developer who treats with respect our desire for an intelligent MMORPG in which ethical exploration drives the gameplay.