I know a good way to fix Veigar E, I think.
New Event Horizon:
When Veigar use E: It rise a pillar pretty much like trundle that knockup the enemy. Then the Pillar start splitting itself to becomes the original E which puts the barrier and slow by 50% movement speed anyone walking through it.
https://www.youtube.com/watch?v=A8FRsDg-LWw
and then it split back to E and becomes a slow like thresh ultimate.