Avid Veigar player with the real scoop
Veigar was supposed to receive some love with the removal of his core item DFG. This however wasn't the case that happened. With his new kit all of his skills have lost synergy with one another.
His Q now pushses the wave regardless of how he uses it. Hes punished for using it to last hit because he now hits other minions with it, other players can just stand next to minions and veigar may or may not hit based on the unpredictable hitbox of minions and champion movements, crippling his trading potential. the enemy doesn't even need to use an escape to dodge it.
stun + meteor is no longer possible because the stun is so easily dodged. Real players with a reasonable ping always have the ability to just adjust. Veigar is now dependent on others to cc and then Veigar is capable of following up with his stun.
since his stun is no longer instant, people can work around it, they have a huge area to walk around in, inside the box. since theres no reason not to be walking around dodging skill shots or getting close the edge waiting for it to end to chase veigar now that hes stun-less. of if he placed the stun in front of you, you can just walk around the stun. veigar is a very immobile champion and very easy to chase.
i can understand the ultimate nerf, in the capacity that veigar can farm for more AP and scale it even higher, or it was too easy to just take out 1 member of the opposing team instantly. and heavily skew the fight. but thats what its short range is for. that and items like banshees veil, guardian angel actually do exist.
Veigars laning phase was severely hurt and as a result, he cant do anything right now. he either spams and pushes to enemy turret, and proceeds to ask enemy jungler to come here. or he just takes a beating because any player moves out of the stun box and they're actually looking at the screen and see "with their enhanced clarity in vision" and just sidestep and avoid whatever veigar can dish out, then they proceed to harass veigar freely and he cant retaliate.
right now hes seated as a very team reliant which revolves around a cc heavy team so he can land his skill shots and get in close to ult anyone. he is now in a niche position where he really needs to lane well and farm well to be able to dish out his maximal damage.
i could see veigars building differently and strangely such as early mana regen to spam, building boots of swiftness and twin shadows. trying desperately not to get caught out. it leaves very little room to build traditional ap.
What should've been done is give his Q(single target) a longer range, a shorter cooldown at earlier ranks, and a lower base+scale damage so veigar is more capable to trade back and isn't as punished for deciding to Q farm or harass.
His stun is useless now, it would be better suited as an aoe slow, at least maybe he could directly place it and have a chance with meteor. If you really thought his stun was too good, you should've either changed the cooldown to be higher at later ranks, or change the base stun amount from 2.5s to 1.5s at rank 5 such that Veigar still has the chance to stun + meteor.
Veigar may be able to farm better and scale even higher at late game, he just cant make it there without some form of escape or protection ability. hes just a free immobile target against the very mobile meta.
TL;DR version - stun actually needs to be instant, thats why its a skill shot in the first place and not a target. and Q needs to be changed again otherwise its counterproductive to use it in laning phase at all.