What if evolving Kha'Zix's Q decreased the Isolation radius? (I.E. enemies are more easily isolated)
One big problem Kha'Zix has is that it's very hard for him to find isolated targets in pro-level games, and he has no tools with which to shove someone out of a bunched-up group on his own. He'd generally have to rely on someone like Blitzcrank to pull a victim out for him to slash apart.
Worse, even a single minion can spoil his Q's isolation damage, leading to a lot of frustrating losses due to a random minion appearing at the wrong time. Can't tell you how much of a bitch that is...
To remedy some of this, and to make Evolved Claws more appealing, I think having Evolved Claws should make the "Isolation Radius" smaller. In layman terms, your enemies would have to be closer together to avoid being Isolated.
Would this be an okay direction, or would it be one of those "eliminates skill gap" bad buffs?