I think in terms of branding and recognizability, the main villain has to be Maleficent. It's the path they took for Kingdom Hearts, Fantasmic, Decendants, Kingdom Keepers. They love throwing her at the top of the pile.
Maleficent conjures up the fears and dark memories of the riders, taken form as Disney Villains, and sends them after us. That's a simple hook that has work a bunch of times before in other mediums.
It's interesting to create a lineup of Villains for the ride, because some already have some significant representation elsewhere at Magic Kingdom like Ursula, the Evil Queen, Captain Hook, Gaston. Facilier was chosen to explicitly not be included in Tiana's. There are picks like Scar, Cruella, Jafar Hades, Chernabog that definitely could be given a good spotlight.
Others feel a bit niche and I wonder whether they'll actually be included or not. Horned King, Mother Gothel, Lady Tremaine, Yzma, Oogie Boogie, Queen of Hearts, Frollo, Tamatoa; All of these feel either limited in spectacle, too out there and niche to include, or like Disney has leaned away from the characters for a while now. The only reason why I think Frollo might have a better shot is that Hellfire was played during the announcement. I'd love Oogie Boogie, but he and TNBC as a whole feels pretty separate as a brand from the Disney Animated Villains brand. Yzma Lever coaster is a really cute idea, but feels very locked in with a specific demographic of millenials and Gen Z that wouldn't age great for a key E-Ticket. Probably the same reason why we won't get RNRC Starring Powerline anytime soon.