Veigar's ult is broken

So I've been playing against a lot of Veigars these days. I play a lot of AP champs, not only midlane, but jungle. I've been playing Lux, Leblanc, Elise, etc.. What I want to talk about is the fact that Veigar's ult deals a massive amount of damage. But not only that, It is a target. I usually poke the opponent Veigar so he can miss some farm. But the Veigar I'm against just play defensively and farms from a range that I cannot reach with Lux's E for example. The games I did today were really annoying. In 22 minutes, the Veigar did 1000 damage with his W (he probably maxed it second). Veigar's overall burst is insane, but all of his spells have counterplay. BUT, his ult being a target that can deals 3000 damage to someone is something that I really hate. A champion should not be allowed to do that much damage with only one spell and the fact that it is a target doesnt help. To counterplay that spell you need a lot of magic resist (in that case I used my Lux's shield, my barrier and my Athenes and it did not do anything against his ult.Don't forget his ult also does a certain amount of his target's AP). 24 minutes in, he completely removed 3/4 of my HP with his ult. Plus, an adc is not going to buy a Zhonyas only to counter Veigar's ult. That's why I think it should need some changes.

Facts about his ult : Primordial Burst Cost: 125 Mana Range: 650 Blasts target enemy champion, dealing a large base amount of magic damage plus 80% of his target's ability power. Blasts an enemy champion, dealing 250/375/500 (+100% Ability Power) plus 80% of his target's ability power in magic damage.