>>23311852D/P? Fix the lack of Fire types on the dex, fix it and improve Honey Trees (HG/SS did great with Headbutt), fix Flint team, improve Underground with better connectivity, improve Seals for Pokéballs, improve Poké Mansion and Swarms to work like Friend Safari/DexNav or something better, improve Pal Park connectivity, keep Vs. Seeker in the game, keep Darkrai/Shaymin/Arceus events and distribute them, keep Battle Tower, add Distortion World and improve it, and please, don't change Wayward Cave, Stark Mountain and Mt.Coronet.
The last one is not going to happen since people bitched so much about Mt. Coronet, the caves and Sinnoh overall that they will probably make Sinnoh linear and casual as possible.
Everything I listed is from D/P except Distortion World. Now, if they could put stuff from Platinum, I want to see Frontier, some roaming legends (but not Cresselia), rematches on the Battleground in the Survival Area and the new move tutors, because that's pretty much what Platinum added. Platinum fixed the speed of the game and added all this, which is all really good, but a chunk of the post game was from D/P too.
If they don't turn the games into baby mode by reducing the levels and giving a worst AI, I think we will be fine.
I also want to ride a Mamoswine on that snow route, when you go to Snowpoint, just because. I would like that.