Now, I'm not saying they should go full Breath of the Wild, but though the original games were linear, they still held a sense of freedom that the current games lack, hiding away plenty of optional areas and letting you fight a good chunk of the gyms in any order, no extensive hand-holding or intrusive cutscenes in every new place you reach. They could take this aspect of the original games and add the Mega Man approach to let players handle gyms or whatever new league system they introduce in any order they want, with the difficulty scaled on how many badges they have while removing arbitrary restrictions like HMs or gateway NPCs. Knowing Game Freak, it'd be too much a task for them, but if they wanted to pander to the Kanto crowd, they could actually take what made those games good in the first place.