A slight idea with Event Horizon

Why not have it work like Viktor's Gravity Field? As Veigar throws down Event Horizon, enemies in the cage are (heavily?) slowed. Meanwhile the walls slowly erect themselves. If enemies touch the wall, they are stunned.

By having like this, enemies have a choice of either: -Staying in the caged area, being slowed, and will have to dodge Veigar's skillshots -Make a mad dash to the exit before the stun wall comes up

My idea might be a little bit too much, but eh. Event Horizon already has quite a long CD, it should feel rewarding to use it successfully. Anyways, it's just an idea.

Give some love~