Improve veigar's E without reducing casttime.
I was thinking, since veig is not really playable competetively, why not make his E a little bit better by adding a small circle in the middle which will also apply some sort of cc. Stun, slow, silence, whatever. Something that makes his E more reliable. Make his W easier to land with a slow or silence inside the ring. Right now there's not really a reason to not just wait out his Stun in many situations. Avoid the W and you're generally not going to die. The area in the circle is so big that you still have enough room to kite people around if you're playing kalista or ashe. Add something, anything really to make his play more viable in high elo.
I added this image I made quick, but obviously it wouldn't look like that. It's just a visual aid.