:???:
I think #3 Lemmy's Castle from Super Mario World was really hard. Although I found most of the game pretty difficult, that level got in my way the most.
Well, Nintendo says they may put Capcom characters into Smash Brothers 4. If they really are going to do that....
Amaterasu for the next game. And good enough to be in God Tier, because, well, she's supposed to be in that tier.
Neutral special: Power Slash. Can be Power Slash 1, 2, or 3...