So why can't Evelynn's Hate Spike target invisible champs?

It's not necessarily a skill shot, but it's not a targeted spell either... so why am I unable to use it on invisible champs? It's not like she is OP right now, so would it really hurt to allow her use her q on invisible champs.

Furthermore, how are you going to buff her to compensate for no DFG? Because eve mid is a thing, and you can't just nerf her that hard with these changes and not give her something in return...