Instead of a Sinnoh remake, why not get a remake of Pokémon X&Y? It's already too late for a third version of Gen 6, so a remake is the last chance for the Kalos region to redeem itself. I don't know if Game Freak can make the hypothetical Sinnoh remake as good if not better than Platinum... Here's my wishlist for the hypothetical Kalos remake.

Wishlist for XY remakes:

Megas for the Kalos Starters (I know Greninja has Ash-Greninja, but only a Greninja with Battle Bond can do that) as well as Megas for a few Gen 6 Pokémon

Post-game episode involving Zygarde and a return of Team Flare under the lead of Malva

Giving both the Gym Leaders and the 3 Friends (Shauna, Trevor and Tierno) more characterization like Gen 5

Rematch of the E4 with new stronger teams, including a Mega for each of them

Gym Leader rematches in the Battle Chateau now have a full team, including a Mega

I know that's too much to ask for, but still.