I'm just gonna list my hopes for a remake
>We don't get a Diamond/Pearl remake, just Platinum
>Game makes use of Mega Evolutions in terms of plot, and don't just have it to the side
>Dialga, Palkia, Giratina primal forms
>Dialga Primal fucks with everyone's speed, evasiveness, and accuracy, including animations
>Palkia distorts reality, changing types based on IVs or something
>Giratina resembles his form from the Generations episode
>Darkrai and Cresselia mega
>They don't hand you legends
>They go further into detail on Unknown and the various ruins, even if it's lore in a library
>More regional forms, preferably from Unova or Johto
>Underground comes back in full force with a bigger map and more to do, maybe create an underground area with a group and compete within there
>Underbosses use Azelf, Mesprit, and Uxie, with you freeing them for the final encounter
>For final Cyrus encounter, have you fight him before Giratina comes, then Giratina frees D/P and sucks you in with him. Then, when you fight Cyrus in the Distortion World, he has Giratina in his team
>Catch Giratina after the League
>Post game has Cyrus trying to rise again, with Giratina not in the Distortion World to stop him he gets Dialga and Palkia again and fights you with them
>Obligatory Battle Frontier with Frontier Brains
>More beach house customization options
>Since GameFreak will probably shoehorn in Ultra-Beasts, have them appear either from a Hoopa sub-plot or Distortion World since it lacks the boundaries of the real world
I know it's a wall of text and unlikely because GameFreak, but I hope that at least some of these make it in.