Veigar's Q being a skillshot that can go through walls

is huge! The fact that it can hit 2 targets makes this an even bigger deal. He can now do shenanigans like Dark Matter one spot from behind a wall and Q another - one of them will hit the target unless they dash out - or fadeaway Q with absolutely no vision of what you're shooting at, and confirmation in case you hit something. That's all without even using his stun.

And consider his Dark Matter mana cost and cooldown buff as well. You can pretty much spam it and scare off anyone. Making people hesitant to walk through Dark Matter spam can help make plays happen for your team.

The best way to play him is completely different now, yeah, but it's not a nerf. He's not bad. I'll miss instagibbing 2 people at once lategame, but these changes should be interesting enough to play with.

Basically, if you're curious as to what has changed about Veigar:

Old Veigar: E is an amazing move, W's usefulness is tied to his E, Q is decent. New Veigar: Q and W are both good moves, E is just icing but when you cast it it's still important that you have W up in case you stun someone.