I'm sure it's just a little difficult for them to make a new skin. Kha'Zix is a pretty unique champion, he has to have a normal form, AND THEN a fixed model for his evolved abilities, (animations aside) so if they have an idea, then they are probably trying to make it work. why not try thinking up some skin ideas and pitching them to the community? like an amphibious Kha that grows large spins when evolved and batlike wings, very fleshy (like jeepers-creepers or something) and there are plenty of amphibious ambush creatures -shrugs-