Kha'Zix evolution rework idea

What if he gets an evolution with every unique champ kill? If he scores a kill he has to devour the dead body and gains an evolution based on 1-4 categories of champions he kills and devours: Assassin, fighter, tank, and mage. He can only gain 2 bonuses per class he devours(only 2 unique assassins give him assassin evolutions, any more unique assassin kills do nothing.)

Assassin kills: Kha'Zix evolves and strengthens his claws, gaining bonus range and damage on autos and 1 on the first kill. His second kill gives his Q %missing health damage.

Fighter kills: First kill increases his sustain, giving him a stronger W heal based on missing health. Second kill gives him a stronger slow on his taste their fear passive and now deals true damage.

Tank kills: First kill evolves his carapace, giving him bonus armor and magic resist. Second kill gives him a malphite type passive, shielding him for %max health until broken.

Mage kills: First kill increases his W mana cost by 30% but gives it 50% more damage based on how far it flies. Second kill puts his W on a charge system similar to Vel'Koz.

It seems weird but the idea is there. Disregard the bonuses if you wish as they are just there as ideas.

Thoughts on this?