Anivia's passive is so irritating

I don't face Anivia mid often, but when I do, it is the worse thing that can ever happen. I play Zed and Leblanc mid, and I can never kill an Anivia. She is a mage, and all her abilities have cc. You can barely hit her, and if you do finally kill her, she turns into an egg. When she does that, all you abilities are on cool down, so you have nothing to kill with but your basic. She has a stun, wall, and two slows(I think). I know most people don't think Anivia is broken, but this is just a place to vent about, HOW BROKEN ANIVIA'S PASSIVE IS.