Other than Queen and Joker (Liz and Ash XI themes), I much preferred XIII OST. I agree with Bakaboy on XIII OST being above average for KOF. I'm not sure what XIV's soundtrack will be like, but I get the feeling, from what little I've heard, it'll be ok-ish to me, like XII, or what the majority of XI was for me.
As for the next showing of the game in Osaka, besides new characters, I agree with Diavle that they get some pro-players in to show what the game can really do. Or, even better, get some kind of small tournament going if the build is close enough to what's going to be the final product. And also, start detailing some of the mechanics of XIV, for what Just Defend will be, etc.