So, what should be done? I for one really like the idea of Urgot, and I feel like his skills are unique, fun, and interesting; at the same time, however, Urgot seems to go in the same box with Teemo and Tryndamere: there's not a lot that he does where I can't think of someone else who can do it better.
One of my team's regulars plays Urgot from time to time, and I love laning with him. In teamfights, I've also seen our Urgot pull off some pretty twisted **** with his ult. As he put it to us, the point isn't really to kill one person or even survive, it's just to throw off their positioning to give our team the advantage. To be frank though, we also have very good communication, and so if Urgot ults, we're going to at least trade our Urgot for their MF (or whoever), and unfortunately that's usually a very good trade for us. Also, our Urgot tends to walk away from more ults than he'd probably admit. --But nine times out of ten, I'd rather that teammate play Rammus or Shen or Udyr. Urgot's fun to have, and he's nice for a change, but Udyr (that's the example in our team comp) outclasses him ten to one.
And our anecdotes are the exception. These are non-ranked games, sometimes against people who boggle the mind that they actually played enough games to make 30 and learned no more than they did. And we build the team knowing we've got Urgot. I've got a friend who rapes face with Teemo too--that doesn't make him good. Ultimately, late-game, Urgot is a one-trick pony who takes a lot of luck even with a skilled player to make the trick actually work.
So what do you do? Would it be enough (or too much) to change numbers? His AP ratios are good, notwithstanding the fact that like a lot of champs he's torn between AP and AD. Or does it take more than that? I for one think you could potentially break Urgot by doing something like causing his Acid Hunter to refresh the duration of Noxian. But even that is just going to improve his laning game, which is already good. Endgame is the hurting, and I have nothing for that.