Hello everyone. First of all, I've tried all the sugestions that you guys wrote in this thread so, I'll talking about my game experience on Linux.
I installed League of Legends under Play on Linux 4.1.6, like futmeK1VYvImO7RT said but, the update that he shared doesnt work. The launcher crashed on wine 1.5.18 and crashed on wine 1.5.20 too
Then, I used Wine 1.5.12 and I could, finally, play. I managed to play with 35 fps (my normal is 60) and without any lag, but, when I entered the shop, the game crashed, again.
So, I tried to make some configurations on League of Legends installation. I reinstalled AdobeAir, enabled GLSL Support and I changed the Direct Draw Renderer to "gdi". I managed to play without any problems (even the shop works perfectly), without lag, with 40 fps, but with some 4:3 resolution (I dont know which one) on my ubuntu screen.
I'm gonna make more experiences and then I'll share with you guy guys.
Hope that I could help some of you.
P.S.: When the game crashes or when you logout the client, you need to close every threads related to PoL, Wine or any .exe that appears on your Thread Log or it'll be impossible to start the LoL launcher again.
If you dont know how to check it, you could install the application "Htop".