What if he was like Neo Geegus (minus the physical transformations) where he would have a mix of characters, that change the move depending on the strength of the button pressed? Mind you, that may be a bit much, so maybe just giving him moves on unused commands (like charged moves) may solve some of this, or making certain EX attacks behave differently.
If an SNK mode is implemented I'd like to see something like Iori/Kyo's command grabs implemented
Neo Geegus video in the spoiler, may help with some ideas at least.
Spoiler, click to toggle visibilty