I am crossing my fingers that the fact that the protagonists are supposed to be older means the plot will be more developed/darker. In my opinion, GameFreak has really let us down with every game made so far. They're the best games in the handheld market, to be sure, but GameFreak has never really pushed itself. They're like a brilliant teenager who slacks off in school because he/she know's they'll pass with only minimal effort.
Just look at the other major Nintendo franchises: Super Mario Galaxy 2 just came out, and it's supposedly the best game since Ocaraina of Time (I haven't had the chance to play it yet). The Mario team pushes themselves, and they took a risk when they made a platformer with a completely new physics system. From what I've heard, practically every level brings something new to the franchise, and that's what has earned it such rave reviews.
GameFreak needs to ask themselves: Why can't they be more like Mario? Why are they alright with reviews that are the same with every new game they release? "The formula has remain unchanged, and although these are still fun and addictive games, GameFreak once again has not brought anything drastically new to the franchise."
Please, GameFreak. Shake things up a bit. If you make a mistake, and the game is terrible because you took a risk, I'll still be there for the next generation. Give us an epic plot. Give us practical online functionality. Deviate from the formula of traveling around a region collecting 8 badges.
An epic story line is what I want in a new Pokemon game, more than anything really. The second would be a Pokemon MMORPG.