Perfect Zed Fix
Casting delay on response from shadows. Something extremely short, like .2-.25 seconds would do, but it may provide real counterplay in an otherwise very cheesy insta-gib. This allows him to farm and skirmish almost just as well, and would really only have a major effect on his laning where there is more specific attention on his movements.
It also heightens the skill cap for maximum reward without just beating him with a number stick.