To people who are complaining that Veigar wasn't popular before and so he can't be overpowered now:
Let's take Poppy as an example. Imagine if Riot decided to significantly buff Poppy without fixing any of her kit's basic design issues. She'd suddenly be incredibly overpowered, just because her kit isn't well designed.
Veigar is basically the same thing because of his ultimate. It doesn't matter how you slice it, an ability that instantly kills an opponent unless they choose to itemize in a way that makes their champion completely useless, is not ever going to be balanced. Veigar's ult needs a full rework, and until then he shouldn't be allowed to be strong.
And no, he wasn't stronger before his mini-rework. His laning phase is much safer now, he farms AP much more effectively, and his W is actually a reasonably reliable ability after the buffs last patch.