As a former zed main...
...I can say that it's quite frustrating when a bad zed wins lane and BMs all game, even though he didn't really outplay anybody.
Ever since I started playing league, I've always looked for champs that made really fancy plays and needed a lot of skill to play (mostly so I could show off to my friends :D). Zed was kind of at the top of this list, after one of my friends told me he was one of the hardest champs to master. Playing zed and getting good with him was fun, and slowly learning how to juke people was fun too.
Zed is a difficult champ to master, and the way I've always seen difficult champs is that they only start to pay off when you get good with them. The current zed kind of violates that, because there are plenty of bad zeds who still wreck lane and get fed, despite needing like a full two seconds to pull off a single combo. So what I'm trying to say is just that some changes are needed to either make zed more difficult to play in general.
I don't mind when I actually get outplayed, but it's just not fun at all to see someone get fed because their champ is broken rather than actual skill.
(Also, by "bad zed", I don't mean people who are completely new to zed and have no idea of how he works, just the people who play him but just aren't good with him at all)