I don't think they can afford to buff him any more in his current state. Basically veigar is a time bomb, if you can't destroy him early, he scales into an opaf monster which often can happen outside of pro play.
I don't think they can really buff his damage or range until they nerf his stun zone a bit, because placing a zone basically still causes whoever is in it to die whether or not they get stunned because of the range and area of his other abilities.
If it were up to me, I would either increase the size of his stun zone, increase the setup time by .1 to .15 seconds, or decrease the placement range of the ability. Then he can afford a buff.
That's my opinion anyway.