Could you make amumus q pull himself to allies and wards?

hmm, I don't think it fits with his goals as a tank. he's not really supposed to be slippery. but idk.

Does he stun the allies? :D

I'd be okay with that and I don't even play Amumu

This wouldn't be a bad idea honestly

I think it would actually be worse, because your allies might block the grab if they are between you and the enemy champ, especially if there are any other tanks on your team. Same with maybe a warded bush: you might grab the ward instead of the enemy.

He has a high win rate across all ELOs and has for quite a while, it's pretty unlikely that they will buff him

I don't think this would work. It would be weird with a skillshot, especially if you need your allies to move out of the way so you can initiate.