that is very true, but i do have to say that the player skill level between can skew some data, I fell for the Lee jungle op thought but couldn't get it down last season, and i cannot play him to save my life, i played less aggressive to his style and hindered my team because of it.
But there are lots of upcoming lee sin mains that try to do "the plays" and fail really bad. You really can't master lee sin in a few games, so lots of messing up is required to get good, so i would venture that for every 1 good lee sin there are 50 bad lee's.
not saying he is a monster, but he does not have any true weakness that counteract what he does offer as pros, he always has something to fall back on and can always cause a meaningless chase.
He can build a tank that does decent damage or a highly mobile dps assassin jungler.
And the lvl 2 ganks ARE ANNOYING, why would that ever be a good idea to give that power to a early game. Every champ has some blind spot, early mid or late that they fall off, but lee still is viable throughout.
Zed, i just think the ability to kill and safely get out is a problem, he just has to walk away from the ult shadow or w and then juke back. "OMG THE PLAYS", NO thats just annoying. This is why i hate leblanc still, you cannot chase her at all. The point of an assassin is to pop a target and have to pray they can get out cus they are all in champs. Talon is the best BALANCED version of an assassin i would say, once he is in he has to run, flash, or pray he gets out.
Mobility is my main problem with these champs, it is too strong to allow so much "RUNAWAY" power on top of a potential Powerhouse.