Ash Williams from EVIL DEAD.
Pennywise from IT.
The Creeper from JEEPERS CREEPERS.
Pinhead from HELLRAISER.
Spawn from IMAGE COMICS.
These are some of the guest characters I would like to see. I picked characters, who would have a lot of variety to their power sets. While I like Jason and Leatherface as characters, I don't think that their stick allows for great, visually appealing fighting game characters. My picks all have quite a bit to them, with the exception of the Creeper maybe. But even someone like Ash Williams could do the Leatherface saw-arm stuff with Necronomicon spells, which would enhance his gameplay by quite a bit. And the others are all reality warpers, who can do whatever they want anyway.