Why complaining about lee sin?
There are many post with "I'm so tired of seeing lee sin in every game, rito nerf lee now." Well yes lee is in a good spot right now but he is not overpowered. He has his own strenght and weakness. And a good lee sin main that knows how to use the strong earlygame to snowball the game deserves to win. Other players that are good with their main champion, performing really well, also carry their team to win. It's just that, because lee sin is a play-maker champion that can outplay the enemy extremly, a lot of people have fun playing and mastering lee sin. If rito nerf him now it would be unfair to all these lee sin mains.
I'm sad seeing these complain-posts with so many upvotes. I admire all lee sin mains out there. Keep it up. I love seeing amazing lee sin outplays.
and
are stronger than lee at the moment
As for your second point, if you intend to say that lee sin is not a champion difficult to master, then what champion is difficult?