The Veigar buffs make him stronger, but don't solve the core post-rework issue—no skill interactions
http://ddragon.leagueoflegends.com/cdn/img/champion/splash/Veigar_0.jpg
I appreciate that they're giving Veigar some more attention post-rework, but I believe it's misguided. The problem isn't that Veigar is strong or weak. Veigar was always kind of weak, but people played him because he was fun. New Veigar may well be stronger, but he's also much less interesting.
The fundamental problem of new Veigar is that his abilities no longer have any meaningful interactions. I don't mean hackneyed "new style" interactions like, "Q applies stacks of X, and W consumes stacks of X to empower R". I mean natural, old-style interactions. For instance, Veigar's old stun, if landed, rewarded Veigar by letting him land Dark Matter and deal extra damage.
New Veigar's abilities simply don't interact in any meaningful way. Yes, it's true, the new ragecage will set up a meteor hit—but it's not clear how anyone gets stunned by his new ragecage, which is now more of a zoning skill, unless the batteries in their mouse run out or they go afk while standing still. The new ragecage doesn't have that frustrating "hit with the edge and insta-stun" mechanic, which is itself a good change, but the problem is that now it relies upon the enemy being a complete idiot (or just unfamiliar with Veigar) to get stunned. That's bad design, IMO. Getting stunned is a big deal, and it shouldn't feel like a random accident.
So while I'm glad they're giving Veigar some attention, I think the focus should be less on him being powerful and more on him being interesting. There are tons of Champions stronger than Veigar, but I don't play them, because they're not interesting to me. Veigar's slated to become one of them.
A suggestion, to keep it constructive
For example, take Dark Matter. Reducing the delay makes it more reliable as a damage tool. It doesn't make it more interesting—just more powerful.
I'd rather see something like keeping the old delay, but adding a knockback away from the impact site, allowing Veigar to use it to knock people into the walls of Event Horizon and stun them. A stun via Dark Matter would feel satisfying and "earned"/"deserved".
Anyway. My main point: I care about Veigar being fun and interesting much more than I care about him being "strong".