The problem with balancing Veigar (or trying to)
Veigar is a great idea for a champ. He's trying to be evil and wants to obliterate all in his path. The concept was that he would cage you and oneshot you in the cage, or if you were stupid enough to run you would get oneshot while stunned. But the "cage" was a tricky, undodgable skillshot stun most couldn't land reliably or escape. So when his core item was removed, he went from decent to bad. Then they nerfed his damage and removed his stun. This was good-intentioned, but poorly executed. Veigar needs to trap and kill people reliably, and neither old Viegar or new Veigar can. Old Veigar only hit his stun when he was good enough, new Veigar barely has a stun. The problem is he was designed to be an evil character that makes you feel helpless as he traps and kills you. So the emphasis is on trapping people in a box OF DEATH. But now the box just dosn't show up. So he needs some way to still catch people as well as have enough damage.
Option A: Keep his identity as a 100-0 mage. This would mean either making his E do some damage or making it reliably stun. How? I don't know, but having a 0.75 second delay on the stun dosn't help. I would recommend some damage aplification and/or a way of catching people.
Option B: Change Veigar into something else. I like the idea of lane-bully Veigar. A skillshot Q, maybe a larger W, an E designed to zone and a beyond powerful ultimate that punishes any mistake. Another option would be doing the old Riot balance-aroo and throwing mobility at Veigar, making him not even need a stun because he can get close enough anyway.
TL;DR Viegar is extremely hard to balance and needs some serious looking at.