Bump...

>>26476569
>Kanto
Make it less boring. Expand on that spooky occult lore about Psychic types and Ghost types we got hints at in Gen I and make that a central thing.
>Johto
Make Celebi relevant. Include actual Johto mons in the region with better distribution.
>Hoenn
ORAS Battle Frontier
>Sinnoh
Better legendary forms for the main trio, sort of like Primals, but not really. Everything about the region is fine, but the Creation Trio look like shit.
>Unova
More lore about Ghetsis and his royal origins. Also more stuff about N's powers and Colress' ties to Mega Evolution.
>Kalos
More lore for XYZ trio. More lore for Lysandre and AZ. Make Zygarde great again, and get him back in a closed relationship with John Gamefreak.

>>26476569
3 This is a really subjective thing, but it would be nice if you could catch fire types in Hoenn a bit earlier.

Pokémon games overdo fun mechanics and themes until they stop being fun. Event Pokémon, legendaries, Team Whatever, local rodent, local bug... this needs to stop.

That said.

Kanto: a bit more type diversity. Another Ghost type, some interesting Grass/[not poison] types.
Johto: the region itself is poorly developed and heavily dependent on Kanto.
Hoenn: tweak the map, those fucking water routes. And more Electric-type options.
Sinnoh: Honey trees? Lake trio? Fuck them. Also, it's lustless.
Unova: gonna agree with >>26476979, more Ghetsis background would be cool.
Kalos: won't opine since I didn't play gen VI.

>>26476569
I'm gonna bump because I wanna do this tomorrow. But I think Unova has the least fixing needed while Kanto and Kalos needs the most fixing.