Please stop asking for Zed nerfs.
Zed is not the problem. The problem started with assassin nerfs throughout S4 and S5, as well as the mana regen nerfs at the start of S5. So, yes, Zed is overperforming right now, because most mid laners became weaker. Mages can poke less, and other assassins have less damage.
And what would nerfing Zed accomplish at this point? The number of viable mid laners is greatly reduced this season already, if anything, some nerf should be reversed so that more mages and assassins can compete with Zed. If an ADC can safely go mid against an assassin even in the competitive scene, you know something is wrong.