Lets Talk About Mundo Pls

His ban rate in ranked was super low last season and now he is one of the most banned champions in ranked. Lets discuss the Mundo!
-Why is he banned so much now but never in season 3?
Mundo is a champion that scales in health and health regeneration due to TWO of his skills abilities that scale with health. So unlike Garen or Zac, any health and health regeneration buffs help Mundo in TWO abilities instead of ONE. He can
New Masteries
*Perseverance: 3/3 +2% of max health per second. *
Second Wind: Increased self healing, health regen, spell vamp, and life steal by 10% when below 25% healt.
With these new Masteries Mundo has become a monster on League and a dominate ban choice by high level player.
-Why not just nerf his ultimate?
This would be fine if it wasn't his core ability. See he has no escape or hard cc. He revolves around not dieing and his champion passive and his ult prevents this. If he gets a nerf here then he would probably need some love somewhere else.
My opinion
Buff Mundo? NO , Nerf Mundo YES!
I think he needs a nerf to his ultimate HEALING but then he should be given some type of a buff elsewhere or maybe a small change in his kit so he wont be completely dependant on Ulting to escape a fight. You guys need to think of it as this, Mundo WITHOUT MASTERIES is terrible. The masteries is what makes him so strong so he needs to be less reliant on the masteries and more on skill. As of now, all the skill needed is landing cleavers.
-What are your guys opinion?