couldn't you have tried more subtle nerfs to veigar's stun first?
most of the time when champions have really powerful abilities, it seems like riot tries subtle nerfs to rein in the power. a slight reduction in the hitbox width, a more obvious graphic to indicate to other players that they need to move, a slight duration increase or changing the effect to be a slightly weaker form of crowd control.
i just saw veigar's new stun and JESUS CHRIST THAT IS SLOW. riot isn't even trying to hide that they want veigar in the dumpster while many champions with crazy abilities only get a tiny slap on the wrist because riot doesn't want to ruin them.