I think I would make a Pokemon game similar to Mystery Dungeon or
Red Rescue Team. You can be the pokemon you want, and evolve when
the time is right. You can find items spawn, too. Unlike the other
games where you are a pokemon, you should be able to see ai
trainers battling and wandering in the grass for a cool catch! You
can encounter trainers and spam buttons to get out of pokeballs,
and it would be free roam!!!
Oooooo sort of bouncing off your idea I'd make a legends game where
you can help build the place from the ground up (there's no
settlement just tents but then you can provide wood and building
materials and at the end of the game you have a town!)
I like the synchro mode from Scarlet and Violet but found it
lacking, so maybe in the game above you can play as your Pokemon
and collect resources based on the type of Pokemon (strength,
ability to swim/fly/climb/etc)
You know how they do raid dens? What if there were 'burrows' that
you could venture into as a certain kind of Pokemon and physically
fight your way through to get the the end where a rare Pokemon is
spawned?