First of all, it should go without saying that every Pokémon must be in the game, and the National Dex as well. I want the game to have two regions. It's okay if the second region is an old one, however I also want an additional sub-region in the vein of the Sevii Islands. The level scaling should be 1-60 in the first region, 60-90 in the second region, with the sub-region having level 90-100 content.
Now, the story in this game needs to be structured closer to that of Gold/Silver: a hands-off approach to the narrative and a good deal of worldbuilding for the player to get immersed in. Don't railroad me. Don't force me to read dull and insubstantial text every ten steps. Don't involve the legendaries, make them hidden and optional instead. Leave me to play the game at my own pace and discover things myself. Most importantly, make sure the level design is explorative, with plenty of dungeons and optional nooks. You may, however, make narrative-focused content as long as it's optional and self-contained, such as with the Looker Quest.

More time must be spent creating and polishing the game's visuals. Make better textures and better animations. It must be optimized as well though - frame drops are not allowed to occur. Make Pokémon as well-animated, good-looking and stable as Luigi's Mansion 3.

Don't make bad battle gimmicks with poorly written lore like Dynamax. Retcon away the multiverse nonsense that started in the Delta Episode. Delete it. Focus on making coherent, enjoyable worldbuilding instead of taking the cheapest possible way out of excusing your mechanics.

Make sure to include fun minigames and auxiliary activities as well! Battles can get stale fast.

I also want the following features to return from previous games:
>following Pokémon
>difficulty settings
>DexNav
>overworld encounters (drop random ones entirely)
>seasons
>VS Seeker
>medals
>PWT
>Battle Frontier (Dome, Factory, Pyramid, Castle, Pike, Arcade)
>Secret Bases

I will now buy your game.