Don't wanna put a large intro, only want to say a few things that can be AMAZING (in my opinion)
First, the obvious things:
·Legendaries, can be banned for PVP or not, in cases like Suicune or Zapdos are not too OP, but go to catch legendaries is an amazing feature that doesn't exist as today, and it's sad.
·Johto and Sinnoh, 2 regions that are amazing and we all love them, no more to say.
·Pokes for 6th gen and beyond, not the regions (are in 3D and too hard, but the pokes are way too easy). Mega's, Z power and Alola can be pretty thick, too.
Now, my personal list of things i'd love to see.
·Day & night cities, themed with more detail and more dark (houses with lights, dark water, u know)
·NDS regions (Kanto&Hoenn), Kanto is in NDS graphics already, i know that Hoenn can be more hard but it's possible.
·In case NDS were impossible, Tile Sets Mods, in the past we have one or two, and were really amazing, but are no longer compatible. That can be a new way to feel fresh the regions and revisit all the cities.
·Battle Frontier (nowadays are working 4 of the 7 places), with their boss and the silver and gold medal for reward, a hard challenge for every player.
I only said the things that I really think are possible, and not making a lot of efford. Maybe it's useless, but I really love this game, this idea, and if I can help to make it better, I will.