It seems like a lot of people would like the introduction of a new main villain, while others still prefer LeChuck to be the main evil. I would love if LeChuck had a female accomplice who would also serve as the main villain. There are many similar stories in media where a deranged sick-minded villain has a beautiful woman by his side doing his dirty work for him, such as the story with Joker and Harley. I always thought it would be interesting if there was a female villain who became obsessed with LeChuck and was in love with him.
Make her into a central character who yearns to please LeChuck, but LeChuck is simply manipulating her and is only using her in his plans to conquer the seas and capture Elaine. I think it would be an interesting and tragic story arc, where you can actually sympathize with her, but must defeat her as well. Sort of a spin on the Morgan character, but this one is obssessed with LeChuck.