I don't think Lee Sin is OP in anyway perse, so much as he doesn't have a weakness of any sort...
The whole dropping off late game weakness doesn't hold any water when you look at both his ratios and the utility his abilities bring. So in short, you can't say he's the hardest hitting champion in the world nor can you say he's the tankiest. But he can hit hard while being tanky. He's no Vladimir in terms of sustain, but he can sustain. He isn't at the level of Kassadin in terms of mobility, but his ability to ward hop brings him to the high end.
So in the end, there doesn't seem to be any clear weaknesses in his overall design even if there isn't anything he's the best at. And it's THAT quality about him that lets him be on top regardless of what happens to the jungle. Regardless of what Riot does to the jungle, no matter how much they constantly change it, Lee Sin will always be able to adapt with ease.
**TL;DR **- maybe he should have a weakness of some sort...or if he does currently have one, maybe it should be much more expressed. Maybe punish him for missing his Q's?
