As has been said a million times, I hope these games let us return to Kalos for two reasons. The first being that obviously the Zygarde plot hasn't been finished and that definitely needs to happen (GF has never left a plot hole that big in any pokemon games, I hope it's not a trend they plan on starting now). The other reason I want this is because, being the 20th anniversary games, I want all pokemon to be catchable between Sun and Moon; well, besides MAYBE some legends, just because I don't want them randomly thrown in like ORAS did. But unless they're planning some serious biodiversity in the new region, it's gonna be impossible to squeeze 700-800 mons into one region. The Kalos dexes combined already add up to ~450, so that would make it really easy to fit in the remaining ~250 mons plus whatever new ones we get into the new region overpopulating it and taking the shine away from the new pokemon like gen VI did.
Other than that, I just hope the story is stronger than gen VI and that the graphics are amazing, but those are (hopefully) givens. A hard mode would be great, but I'm not expecting it, honestly. A little type balancing wouldn't be bad either, but not too much as I think the type chart is pretty well balanced as it is. Maybe make fairy weak to psychic? It would make sense thematically (logic beating magic), and would make psychic better while also nerfing fairies defensively. Or maybe making psychic resist fairy would be better. Some buffs to Ice and Poison types would be welcome too, idk how likely that is to happen though.
The last thing I want is a varied landscape. I want everything: deserts, deep forests, rich dungeons, snowy mountainsides, elegant water routes and underwater caverns to explore. I hope this region is really an "all coming together" type of game and incorporates everything from the past regions in terms of geography and climate. What if the seasons returned, or the underground from gen 4? That might be too much to ask but it would certainly make my day.
