Your Roll looks ten times better than the one in MvC!!

Altough you could also try doing a TvC styled Roll sprite, just to see which one could work better...
Regina is awesome, but I think it would be odd of her to use her worst enemies as strikers and abilities. :S
Perhaps they could work as part of a minigame or even a boss character? Like the Allosaurus from Dino Crysis 2...
heck, we could use lots of old CAPCOM Arcade and console bosses... Astaroth from Ghosts n Goblins, Yami from Okami, the Queen from Lost Planet, Nemesis(?), who knows, the possibilities are endless...
Altough I would'nt have them as the final boss, I'd rather have them as maiby an experiment or simhilair released by the real villians...