Working on a third-version FRLG type hack with
>day and night cycle
>remapping to make Kanto look more like Gen 1's urban aesthetic
>Johtomons in Kanto from GSC as 1% encounters and rewards from the professor for encountering "new species"
>crossgen evos included from the start
>rock smash and headbutt mechanics
>bigger Sevii Islands
>Battle Tower (can't get the battle Frontier mechanics right, sorry)
>Johto postgame
>running indoors

Any other suggestions? Nothing about including Gen 4+ mechanics or Pokémon. Something that could have been feasibly done in 2004 when this game came out and wasn't done for some reason. Ideally I'd still like this to have compatibility with legitimate carts