I guess I don't get the whole "ego" thing. He trashtalks a lot, but when it comes down to raw skill, he's shown up more often than not. There is a reason countless pros have called him one of the best ADCs in the world.
Doublelift has pentakilled Fnatic, Curse.eu and M5/GG. While he has been on CLG, he's carried the team to wins against M5/GG, Fnatic, Najin e-mFire, Startale (which would later form KT Rolster B), SK and a bunch of other teams. Teams play team comps that specificaly revolve around diving him and killing him. Regardless of whether you think he's immature or an asshole, the dude is 100 percent the most talented North American player, I just can't see anyone arguing for any other NA ADC.