You would have to remove amumu's mana costs to match his viability compared to junglers likes xin

I'd say he needs an update in general...he'd still be a sad mummy, but he should look cooler.

This is why I stopped playing amumu years ago. If you dont get a blue buff you're basically fucked pre 20 minutes. His ganks are bad before 6, his innate tankiness isnt bad but people just ignore you after your ult is down, he doesnt deal much damage unless he can stick to people(Which he struggles doing nowadays)