Doctor Zilean (A DOCTOR WHO SKIN!)
Ok, be honest with yourself. You Whovians totally know the idea of the one guy that controls time in League and has the ability to regenerate instead of dying have a Dr. Who skin is BRILLIANT! It'd probably be a legendary skin though, considering it would change during the game.
Lets break down his look. Obviously everyone wants to see the tenth and eleventh. I would, however start him off looking like the 1st Doctor. Instead of Zileans giant clock on his back, he would have a knockoff of the Tardis (painted red maybe, we don't want any copyright issues here). When regenerating, he would transform into the most iconic doctors, the 4th doctor, the 10th doctor, and the 11th (if they really take the time to fit that all in).
Skills:
Q: Alright, I'm having trouble coming up for what could replace the bombs.(any suggestions would be appreciated). I was thinking of a fez that floats over their heads till it explodes.(shrugs)
W: In place of the speed up or slow down sounds that it normally makes. The sonic screwdriver sound would play, speeding up zilean, or slowing down enemies as usual.
E: All this does is lower his cooldowns, so I suppose he could say something that the Doctor is known for saying. Allonsi
F: THIS is where the magic happens. When Zilean dies, instead of coming back as his usual self, he will have regenerated into a new Doctor. However, if he dies as usual, he starts back as the first Doctor. Using this ability on friends doesn't change Zilean's appearance.
Honestly, the complexity of this skin is simply in the ult, and there isn't too much to affect with it, aside from that. The animation styles of Zilean's usual self is pretty simplistic since he doesn't have fancy movements. Not sure how you'd fix the floating around. Unless you have him hanging out of the Tardis door or something. His basic attack would probably be the throw random objects from inside the tardis. His normal Death animation would be him falling inside the tardis and it going out of control and exploding. And the recall animation...come on...you know it already.
For those who don't know the show that I'm referencing. I'll post a link for the doctors in specific and maybe a link to a clip of the recall animation.
http://www.doctorwho.tv/50-years/doctors/first-doctor
http://www.doctorwho.tv/50-years/doctors/fourth-doctor
http://www.doctorwho.tv/50-years/doctors/tenth-doctor