I apologize for ever doubting our goddess Sakutena. We get Mewtwo and a balance patch in two weeks, along with Lucas in June. He's way too good to us.
Seriously though, Diddy will probably get nerfed hard. Looking at what Sakurai did to Rosalina and Greninja, he's merciless. I hope Rosalina and Greninja don't get nerfed anymore (although running Shadow Sneak will probably be removed since it was taken out of the 3DS version). I strongly doubt he'd buff Zelda, but a boy can hope ;-;
edit: Regarding amiibos:
I think they're amazing. All of the announced smash ones look really good so far. I definitely want Jigglypuff, Greninja, Bowser Jr., Mewtwo, and Lucas while I might get ZSS and Paletuna.
The yarn Yoshi amiibos are adorable and I need them. They're a really cool idea and it just shows how creative Nintendo can be.
I don't care about Splatoon so meh.
Amiibo is Nintendo's newest thing, so they're trying really hard to promote them. I think they're a great idea and I don't think they're going overboard with them.