So you basically want him to go backwards.No, like Wario is just some sort of evil Mario, Mario uses his arms to smash attack, not his shoulder. So Wario should copy Mario while making it new.
So use a back arm.
Wario managed to go from an evil twin trope to a unique character with his own identity, personality, abilities and aspirations... and you want him to just be "evil Mario" again?
That's like wanting Luigi to just be a color swap of Mario again.