I think Riot made a fatal mistake here.
They thought Zed players generally build AD thus by giving him the new passive and removing the old one from his W, Riot gave Zed a new big opportunity that is having lots of AD even when building armor and defenses.
Nope not really. He won't be doing any damage if he builds tanky.
Not tank, get 
as last items for strong dps.
No, this isn't a damage buff from his ult they took the ad away from his shadow, in order to get the SAME damage he used to he now has to repeatedly assassinate high ad targets. Building tankier than before just means he does far less damage and also doesn't get kills that would give him any bonus ad.
