Oh, there's a ton I want from Sun and Moon/Generation 7.
1: Give us a good story, and characters with actual personality. X and Y were massive disappointments in the story and character department. Most characters had one trait(I'm looking at you Tierno...), and had no impact on anything at all. They were just filler, except Lysandre, who had some character, but he still felt kinda empty. Much like the story. Basically, give us a story that's like Black and White again. It doesn't have to be as good, but make the adventure feel more lively.
2: Give us better villainous team. This sort of relates to the first thing I want out of the new generation. I don't even want to explain XY's screwed-up child of Team Rocket and Team Galactic with all the life taken out of it. Just give us something with IMPACT TO THE STORY, please.
3: Actual evolutions to older Pokemon. Sure, Mega Evolutions can be kept around, I don't care. Just give us actual evolutions to some older Pokemon. I fear Megas would take away any potential from older Pokemon who need it, due to most megas making good or popular Pokemon better, or even Broken.(Kangaskhan, Fanservices X and Y, and Ol' Ray.)
4: Get rid of that Generation 6 EXP share. The old kind was a mix of balance, and helpfulness. I'd like it back.
5: A greater challenge would be nice. I'd even settle for Challenge mode settings like BW2.
6: Pokemon who follow you would be nice. It doesn't have to happen for the games to be amazing, but It'd be nice.
7: Less fanservice. X and Y was so obvious with the fanservice...Can we have less, please? It would contribute to it feeling like a new game.
8:An expansive postgame. Platinum and BW2 style. Make the reward for beating the game feel like something well-deserved. Not just one useless sidequest(AHEM XY LOOKER).
9, and possibly the most important: a region that feels alive.
Ah, the old days of 2011. Black and White had so much to see, so much to do, and it just felt alive. It felt immersive. I want to see Game Freak give it their all in this one. Make the region have little secrets here and there. Remember Black and White's route 1? the flowing petals and whatnot? Or the sandstorm in the Desert Resort? What about the crowds and lines in Castelia City? How about those people you can talk to to add something to the area's music? I'd like some more of that. Make the adventure feel like an adventure, like the days of Sinnoh and Unova.
Basically, where X and Y was(In my opinion), a huge leap back from Gen V, I want Sun and Moon to be a huge leap forward.