My main concern in any game is, far ahead of anything else, whether there is an interesting and engaging narrative. Without that, the game can be as awesome as all , I'll still be bored. (Star Ocean 4!!) The downside is, obviously, that I won't know until I play the released game to the end. Lurvely conundrum, entit?
Next up is actually the music - yes, I'm funny like that. I have heard very little of the music so far, and what I HAVE heard didn't fill me with anticipation...
Besides that: gameplay mechanics (and, if applicable, mini-games) that don't require a degree in relativistic space physics to comprehend and properly apply. I mean, yeah, I think flight sims are cool and all, and you CANNOT get any more complicated operation than that, but in a console RPG I just want to push a few buttons and see my controlled characters smash things at random... REASONABLY challenging, too! (DAMN YOU, Kingdom Hearts 1! And KH2 for being a push-over!) I'm a little worried by the intricacy of the play-dress-up mechanic, and what they've unveiled about this iteration of the paradigm switcharoo. 13-2 had some really demanding twitch-matches (... that flying Vercingetorix look-alike, and Lightning's DLC) - which I could handle, but only barely.

Finding out about the extinction mechanic raised an eyebrow - finding out there are side quests that award experience points, á la D&D, will raise the other 'brow.