Probably gonna get shot but... I never want a second Subterranean Animism. The overtuned difficulty drove me off from it. Not only the patterns, but also how annoying it is to open new stages for practices, requiring a little too much dedication and perseverance through repetition that it made me stop having fun on it.
The new "partner" system, without any shot I could be confortable with, combined with bombing from MoF... how streamlined getting Extends were... ugh.
But I guess Zun won't go back to it.
Anyway, besides that I never want Marisa to stop being playable in main games. So even if there's a fresh start with a new canon (like EoSD), I hope Marisa carries over. Don't really care about the personality and design, as long as it's a witch that shoots love and lasers.