It's not that Wukong sucks or anything, there's just better for each thing. Like someone else mentioned, he's a niche pick. I love Wukong. I got my ass whupped by Wukong when I started playing this game back in January. I've been fascinated with him ever since. The nerfs apparently hit him mega-hard, but I still like using him for jungling. In terms of when I pick him though... this is why:
I use three junglers competitively: Volibear, Shyvana, and Wukong.
I use Volibear because he's a mobile tank with really strong ganks and decent aoe. He can still dish out some serious damage without AD items with his W. He's my safest jungle pick. I default him if I'm first pick, and pick him if I want to shut down an enemy champ early or gank lanes hard or we just need a tank.
I use Shyvana because of her silly fast jungle clear. She's not terribly dependable for ganks because after I burn an exhaust on one lane, it's hard to gank others unless they have CC, but her counterjungling and pure teamfight ability and lane clear for mid to lategame pressure is ridiculously insane. I tend to pick her if my team has decent CC already or I'm up against a jungler I can easily shut down or a jungler I need the fast clears for to keep up.
Wukong... he doesn't excel or beat either Voli nor Shyv in what I use them for and he's blue dependent early-on which is usually a big hell no for me when jungling. Blue should go to midlane or AP top. I go Wukong if I want a happy medium, but his ganks aren't as strong as Voli's and his pressure isn't as strong as Shyv's. It's rare I use him because there's simply no need to. The ult is nice for teamfights and an instant kill with a Yasuo on our team, but that's about it, unfortunately. He's a solid pick, but there's no reason to choose him over someone else if you're trying to do something specific for your team comp. I will say he's better in terms of being an offensive presence in a teamfight that's hard to hit, but only because of the last part. I carry with Shyv and decimate in teamfights. The escape isn't needed. So... yeah. Wukong doesn't have much of solid reason for being picked as opposed to anyone else unless you want that balance (which is useful sometimes, but when out of mana... sol.) If you want balance without the mana dependency, there's Lee Sin who does everything he does, better -he even counters Wukong. The only reason I pick Wukong over Lee Sin is because I don't like how Lee Sin feels to play. There's no logical reason though.
:\ Wukong may just need a rework or something. He's not in a bad place, but he's not in a good-enough one to be seen as much as many other champs.
change with the lose of 5th pot and worse stats may have impacted his first clear that people don't feel he's competitive or something.
