what about a swarm% where you have to rescue the musician and finish his quest to get all the musical treasures? honestly you could do that for all the endgame items, rawrpaws already said extra hand% and solo pellet%, but we can extend that with infinite sprint% and pluckaphone%, and then maybe have one where you have to get all of these items, although honestly im not sure how many people would run them. maybe 1000 pikmin%, where you have to get 1k grown? that could be interesting, cause which would be faster, doing areas and getting new enemies, or just focusing on pellets? might get kinda stale though...
personally i think the switch has the best version of the controls for 1 and 2 once you get used to them, and i dont use motion controls