People here and elsewhere judge Zed's state of balance solely by his ability to assassinate someone
Every time someone tries to bring up the topic of Zed's state of balance, they're bombarded with posts talking about how "you can QSS and Zhonyas his ult" and "Zed is fine because he can kill only one person."
A lot of people need to realize that this champion and many others is not solely about one aspect of their kit. Zed can assassinate, yes, but he has a lot of other things in his kit that causes him to become oppressive and powerful at times.
I have no idea why everyone idolizes this champion as some kind of a "perfect model of an assassin." No, Zed is not balanced because you can QSS his ultimate. No, not every assassin design should follow Zed's design.
The champion has a lot of damage and mobility, which, yes, makes his assassination threat very high. He is one of the safest assassins in the entire game. He can outduel almost any champion in the game. These two factors make him one of the best splitpushers in the game. He is also one of the few melee assassins that can poke and CS from a great distance. Not to mention that all his spells don't use a resource, making him a sustainable champion in lane. See? There's a lot more to Zed than his assasination potential.
Every time Zed is popular and overpowered, this section of the Boards is filled up with complaints about him, similarly to the complaints pertaining to Rengar right now. They bring up the exact points that I just made here. Yet, when he doesn't have people actively loathing him with all of their will, people defend him with shortsighted arguments that others read and perceive as valid.
The next time you defend Zed, say something more creative than "zhonyas," especially considering the fact that in the current patch, it's in the weakest state it has ever been in its existence.