>Mount Coronet is super simplified, or worse, turned into a long hallway in the middle of a wild area
>Dynamaxing is SOMEHOW in the game
>The stat trainers are shoehorned into the overall plot as secondary starters, with Riley taking center
>The Game Corner is cut, alongside the OST
>Battle Frontier is replaced with the Battle Tower, Palmer replaces one of the Tower bosses
>Diamond and Pearl's regional dex instead of Plafinum's, national dex is regional+a hundred other Pokémon
>Special hour long Darkrai plot after the Elite 4 where you fight Gigantimax Darkrai in a raid with the stat trainers
>Honey trees are gone
>Planting berries is gone and replaced with gen 7 and 8 berry trees
>All the cool events like Shaymin and Darkrai cut in favour of Mystery Gift distribution
>Sinjoh ruins are gone
>Pokétch is severly nerfed
>Global Trade Station is gone together with all the mechanics it brought
>Sinnoh Underground is actually improved from the original, but with limited online options and trailing behind the secret bases in ORAS
There are your remakes.
I hope you enjoy them.