Maybe I'm just a huge Final Fantasy mark
but I'm pretty optimistic about the characters in the game after seeing that PAX panel. I agree that it feels like the characters are really going to drive the game forward, and honestly that's been a staple of all of the good Final Fantasy games. Characters are the strongest parts of IV, VI, VII, Tactics, IX, X and XII. In VIII and XIII they are generally the aspects that people are negative about, which colors their opinion on the game. Even games that aren't all that stellar (looking at you, X) are redeemed by having memorable characters at the very least.
I kind of have a strange soft spot for the boy band of XV, and I'm really looking forward to seeing how the game shapes up in the months to come. I think there's an awful lot of potential here. Hopefully it isn't squandered.