It's going, I have had a bunch of larger tasks that distracted me from working on him.
Some current problems I have with Mundo is he becomes extremely problematic in small scale fighting (twisted tree line) and becomes rather useless in large scale fights (SR). Some other issues is that he does not scale that well into the late game, with the exception of having tons of health.
I would like to tone down his power slightly on TT and make him better on Summoner's Rift, also I'm hoping he will fall into the right place for Dominion with these changes.
I've also been trying hard to keep the feel that Mundo is extremely powerful at low amounts of health, it's generally a very hard thing to pull off in large scale fights such as 5v5 scenarios but I'm attempting to make it work. His kit generally tries to do this but instead of trying to homogenize Mundo to make him better I'd like to keep this feel and try making the kit lend its hand to this even better. Also, more importantly Mundo still needs to go where he pleases .
I don't want to go into very much detail about what I plan on doing with him, but a few high level things I'm fixing is Base Stats, allowing him to scale into the late game, and changes to his ultimate to further help him sustain at low health so he can take advantage of Masochism.
After the changes Mundo would be a good jungler or a good top lane. He would also have a lot of viable build options. HP stacking Mundo which is a generally more tanky build with sustained damage, or a glass cannon mundo that goes lots of AD with big crits.