I think they can be way more innovative while keeping the same combat system, have better camera (more third person) and graphics with a larger world that doesn't need to be open world, have verticality, have much better dungeons, actually include previous and end game content people want (don't try and sell it to us down the line), etc. It would sort of be like XD but a main Pokemon game with a lot more content while taking cues from classic Zelda for game design. Sometimes I feel like there's a bigger difference between OoT and Majoras Mask than I do Pokemon RB and SM when it comes to its single-player campaigns, having well-crafted dungeons, puzzles, unique items, secrets etc does that.