Mundo way too strong??

Ok, so I know I may get some crap for talking about Mundo, but theres a reason he has a very high ban rate. The only thing I have to say about Mundo, is that his regeneration is WAY too high, especially late game with and . He literally is unkillable. I recently had a ranked match as Malzahar, and I was reasonably fed going 10/1. I had and was working on a . During a teamfight i get pushed back as Mundo just steamrolls through the whole team to reach me since I am the most fed on the team. I would have died, so naturally I ulted him while he was taking tower damage. However, even as I used malz's e, and ignite, and had passive, HE STILL REGENERATES faster than I deal damage. Like seriously how the hell do you kill him. I doubt even getting would have made any difference. I just dont understand why he still has no nerfs what so ever. Even just a ult nerf. I don't think I am being to harsh either, because how is it fair to fight something that doesnt even get dented after applying all these abilities on him. I could go on and on about him. Or . I apologize for the way this is paragraphed but I just needed to write this because I havent seem much about Mundo nerfs.