Hello there Ladies and Gents, I know what you may be thinking, "PulseFire Ezreal has Evolving Armour blah blah blah." But Viktor should be the one to Gloriously Evolve. He should have a Legendary Skin where he starts the game as he was before his inventions' credit was stolen. He would be a man of high prestige and his Lazor could just come from his staff. At Level 6 when he activates his ult, his appearance changes and his clothes are now torn and raggedy and he now sports his Mechanical Arm. He could lurch about and act somewhat insane due to the fact he's pissed as hell and going insane because of his credit being stolen.
When he levels up his ult for the Second time, he would transform to look like his normal skin but his armour is re-vamped and he looks hella more bad-ass. Then finally when he upgrades for the last time, he should turn into fully Augmented Viktor and have massive armour and his entire body and limbs are made up of whirring machinery anywhere from gears to levers. Keep in mind all his animations and what he says changes as he Evolves. (Although I like his dance so keep that :3) Another Idea I had was that when Viktor kills an enemy champion, you slowly see them start to decay away until only their skeletons remain EXCEPT, their bones are now Machinery parts and can range from brass, to gold, to silver, etc. And he has a special quote that says, "Yet another has joined the Glorious Evolution" when he kills something.
Here is a picture I drew in Paint: (Zoom in to see clearer)
EDIT: Made a new Thread detailing even moar about Viktor, go here: http://na.leagueoflegends.com/board/....php?t=2328547