>Shouldn't they just take Gen 1-3 and put them together into a huge world like Breath of the Wilds Hyrule?
Bingo
We need an actual full scale open world adventure with branching paths that meet in the middle, where you use your Pokemon's moves to solve puzzles etc.
The last 20 years also need to be disregarded because Gen 4 is objectively when the series and designs started to go bad.