The only changes that I would like to see have more to do with the amount of moves/pokémon of certain types and the strength/accuracy/secondary effects of some moves. But I wouldn't actually want to change any of the game's mechanics. The classic rock-paper-scissors gameplay works great in my opinion and we already have priority moves, status inflictors, stat boosters, entry hazards, et al. What else do we need? Anything new additions would complicate the system beyond what I'm comfortable with.