Mundo's cleaver volume got nerfed as well. So he's probably the worst pick for the jungle now.
He's top sucks too.
Pretty much all top champs have better sustain then mundo nowadays.
He's missing his element cuz he won't land that many cleavers on enemy champion in lane, and all of his skills take up hp making you can't do anything at all. He's cleavers wouldn't do anything if the oponent is smart enough to stay/fight behind minions.
He's base attack dmg is low so that it's so hard to last hit without the E buff. However, when you use E to last hit, you've just used up your health, and lost your trading potential with your e on cd.
He doesn't have reliable gap closer, so tp gank would be unreliable(especially with the volume nerf to his cleavers).
His dmg late game falls off heavily and has no reliable cc or peeling.
some new items might appear decent on Mundo, aka dead man's plate, titanic hydra, there are just so many champs that are way better with those items.
(fyi, darius's q heals more than Mundo's ultimate most of the time).
Don't play mundo. Get him refunded for 3150 ip.
Also, uninstall. There are some riot employees playing among you in some games. When they see something unfair to them in a specific game, they'll try to nerf it instantly.
This game is not worth playing if such thing keeps happening.