So Veigar's E got nerfed due to being unavoidable, which was a justified nerf.
However many other champions have the exact same problem, with varying degrees.
So here's a list of them all, I'm actually pretty sure that Riot will work on this in the next updates, I'm posting to start a discussion on how to nerf/buff/rework.
Take note, saying that you don't agree is fine, but going as far as flaming and explaining how to counter ~~your main~~ a champion should be avoided.
Additionally, take note that it is the truth that zhonyas, QSS, and other items can nullify these, but if a champion forces your item path, it **is** unbalanced. Everything should have potential to be outplayed.
Annie - 8/10, With a full unavoidable skillset with AOE and stuns.
Viktor - 6/10, His ult is unavoidable but has no hard crowd control.
Fiddlesticks - 5/10, Exploits lack of vision, if he jumps you, you die.
Zed - 9/10, There's been enough discussion about this, the ult has to go.
Katarina - 10/10, Another full unavoidable kit, this time with a flash every few seconds and enough damage to kill entire teams.
Talon - 6/10, He's what Kat should be, but he still has an unavoidable blink.
Akali - 7/10, Unavoidable ult and kama for easy kills, but only one person at a time.
Amumu - 10/10, Self explanatory.
Blitzcrank - 6/10, A less overpowered Amumu.
Cassiopeia - 7/10, Unavoidable ult and fangs.
Diana - 3/10, Not really unbalanced, but still uncounterable ult.
Fiora - 9/10, Two targeted dashes and the most unbalanced ult in the game.
Galio - 2/10, He has no dashes to move in, but still has an uncounterable ult.
Gnar - 5/10, Almost uncounterable ult, and he has a dash to get in with it.
Gragas - 2/10, Technically you can avoid his ult, but it's ridiculous.
Janna - 3/10, Unavoidable ult can potentially be gamechanger, but not unbalanced.
Jax - 5/10, Targeted jump that is usually followed by a stun, both are broken.
Karthus - 9/10, He can still get stunned while casting, so there's that.
Kennen - 3/10, Ult is quite a punch but can be outplayed.
Leona - 2/10, See Gragas.
Lissandra - 4/10, Telegraphed blink, but still has uncounterable ult.
Lux - 6/10, See Gragas.
Malphite - 4/10, See Gragas.
Malzahar - 1/10, See Galio.
Maokai - 3/10, The dash is broken.
Master Yi - 6/10 self explanatory.
Nasus - 4/10, Unavoidable E, you will have a bad day.
Nautilus - 4/10, Unavoidable R, but not instant.
Nocturne, 1/10, Unavoidable but very balanced ult and kit.
Pantheon, 2/10, Unavoidable stun/dash, also balanced.
Rammus, 7/10, Unavoidable taunt and nigh-unavoidable engage.
Rengar, 9/10, Rengar inevitably ults your face, point-blanks you with his bola and still has enough damage to kill you.
Riven, 10/10, One of the most annoying/toxic champions to play against, but the only unavoidable part of the kit is her ult. The high score is simply because she doesn't need an unavoidable execute ult on top of her kit.
Teemo, 10/10, Exploits lack of vision like Fid and Q and autoattacks are unavoidable.
Syndra, 6/10, unavoidable highly-damaging ult.
Taric, 4/10, Unavoidable stun.
Tristana, 7/10, Unavoidable ult and E.
Vi, 8/10, Self explanatory.
Warwick, 7/10, Self explanatory.
Xin Zhao, 6/10, Self explanatory.
Wukong, 9/10, Self explanatory.