Kha'zix needs to be able to use Taste Their Fear (Q) on towers

is a fine champion early-game with his amazing ganks and isolation passive. His only real problem comes later in the game once the enemy team starts grouping.

Another assassin has this problem too. He goes by the name of Shaco. However, unlike Kha'zix, Shaco can still be useful late-game by splitpushing.

I think Kha'zix could healthily fill this role too. He should be able to use his Q on towers, like Rengar.