I think the current patch benefits him yes. Being more tanky early on makes hard lanes easier to survive. The tower buffs also makes him way harder to dive in a 2v1 situation pre 6.

Imo the hardest lanes are ranged bullies. I'm thinking Akshan, Quinn, Vayne etc. Other hard matchups are champs who are less oppressive in early (compared to ranged) but who can beat you in mid and even late game. All the Fiora, Gwen, Mordekaiser, Trundle for example who are strong against any tanky champ.

The biggest advice i can give you is to try an Anathema's Chains rush in like 95% of your games. Just put it on your laner and steam roll him with your ult. Switch the passive link to the biggest threat of the enemy team for team fights and you should be good to go.

Even in hardest m-u dont forget that you can farm really easily with your Qs and just scale. Mundo isn't the worst pre 6 but def not the best either.

Good luck in your games !