Hopefully someone that isn't Ganondorf, the guy is dead(AT and DT), and sealed(CT), give the guy a rest, before you revive him or break the seal again, and let another villain shine for once in a console game, occuring in present Hyrule.
Vaati, would be a good idea, we still are missing part of his story(the one between MC and FS), which could be cover on a console Zelda, afterall he pretty much haven't gotten a big chance to shine on home consoles, he only had FSA, and he ended up being a puppet for Ganon.
Demise, would also be interesting idea, but sure, for this, unless they retcon some of Demise's lines, we may aswell not be playing as Link, but play as the Goddess Hylia herself, which would be quite the change for the usual Zelda formula, and would bring to some interesting gameplay.
COMG guide to points: 1 point = Raging. 2 points = Beasting. 3 points = Tearing it up. 4 points = Berzerk. 7 points = Rampage. 12 points = Burst. 15 points = god mode. 20+ points = DIVIDING BY ZERO!!! 40+ points = Youkai (originally Pokemon).
-1 = Negabeasting. -5= NegaRampage. -10 = NegaBurst