People will be happy if there's new characters, and if old ones make (a) returns.
People will be angry if there's new characters, and if old ones make (a) returns.
I'm glad I'm in between or this might suck. :V
But really. Sometimes you just need new characters to make the story feel right.
I might think ZUN could finally put Mima in a new game, but I honestly think everyone's kinda legitly pissed him off enough that he won't. =X
ZUN just tweeted that he's going to have Mima return in Stage 5, but she will be killed before her dialogue begins and the real stage boss steps in.
Killed
ghost
.... Yeah I can believe that.