Mundo's rank 1 ult
sucks right now. In fact it might be the worst rank 1 ultimate of any champion currently.. It costs 20% of your current health and then heals you for 40% of your max health over 12 seconds. So if i have 1000 hp, ult at half health i go down to 400 hp. Then i heal back to 800 hp after a whole 12 seconds.
Basically all mundo's r1 ult does is heal for 300 hp and give him 15% movespeed for 12 seconds. And it has a horrendously long cd now (100 seconds) early game. I think everyone can see why mundo fell out of favorability now.
A lot of people don't like playing against mundo but come on now. Why make the champion garbage because he saw the light of day for 2 patches?