Yeah, I didn't reply to
SnakeFighter64
at first because I didn't want to take over another page with all my paragraphs lol.
But yeah. Jill in particular had a unique moveset in MvC2 that could be used for heavy influence. Saying that the RE protagonists "just run and shoot" and thus they can't have a unique moveset is like saying everyone with a sword just runs and swings their sword.
Some of the hallmark weapons of RE that aren't
guns are the combat knife, the grenade launcher and the RPG. Snake only has one of those. Jill (since I'm using her specifically in this scenario, even though any RE protagonist could work) would likely differ from Snake's weapons-heavy moveset by incorporating her knife in sword-like play with less disjointed hitboxes, a counter since using counter weapons has been a mainstay of the RE franchise, a sideB grenade launcher possibly with multiple types of grenades (explosive, fire, flash, acid) and an incorporation of some sort of BOW call in a similar way that Zelda "calls" her Phantom. A la MvC2.
Moveset potential isn't what would stop an RE protagonist from getting in. They've had 5 unique movesets already made for other fighting games and have 23 years of games from which to draw inspiration. What would stop them from getting in is Nintendo/Capcom not wanting them in. Nothing else.