I don't think its too much to ask..
1. All his spells are based on HP.. Yes the passive is suppose to fund this. But the nerf hp base stat, hurts too bad.
2. Yes, I play mundo a lot. But even in games where I do great... I don't feel op, strong yes but I dont go into team fights killing everyone in 3 seconds. I have had games where teammates have actually raged cause I have gotten kills, instead of them (as they say it, mundo can't carry). Which I partially agree. He can win games. But he isn't going to carry 4 other teammates that are lacking gold.
3. With the new magic and armor penetration he doesn't scale late game as much, he is easier to kill than he used to be.