Starting with his Q, I always disliked its old usage of just poking your enemy down a ton. I did a lot of research when I first started playing in how to play Veigar since he was one of the reasons I got into League but I was disappointed when most recommendations were to use it solely for harass and pick up farm whenever you could later. The fantasy with Veigar, at least to me, is his limitless potential of getting ridiculous amounts of AP; not harass my opponent a ton with my Q.
That exactly what I though first with old Veigar, so I get your point. When the new Q was announced, I was like "Finally, I can focus on farming !". But I wasn't expecting a removal of my kill potential as a trade-off.
The changes Riot made make it more interactive where I can decide how I want to use it. Do I use it primarily for farm to get a steady AP gain for late game damage? Do I focus on using it for harass do to its high missile speed? Or do I mix the two and try to fire through the minion line to pick up a point of AP and keep them from just wading in minions? Another thing is now that it can hit two targets I can actually roam now without feeling like I'm missing an opportunity for more damage as well as providing more utility for it in teamfights.
That's where I disagree. It's really hard to poke AND farm in lane. Even harassing is nearly impossible as long as the opponent stay behind his creeps. I think that there is no reason to harass with new Veigar. You usually poke to force a recall, or to all in when they're low enough. But if they recall, you will just farm more, catching up what you lost harassing. If they stay, you're still not sure to get a kill because they can avoid everything but your R, that does maybe 300 damage at 6 if you didn't farm.
As for roaming, I think that's not a good idea when you're farm-reliant and you can't 1v1 anyone. Even following the roaming enemy is dangerous if the river is not fully warded.
Veigar's E is now more difficult to hit, thus making his burst and harass rotations harder but I don't feel like that's a bad thing. While I am upset that I now am even more at risk of being ganked since a reactionary stun is less likely, I fully understand why it was given a delay. I played support Veigar bottom lane a ton with a friend of mine and the instant 2.5 second stun at max rank was obnoxious to say the least. It may not have just been a targeted stun but with a bit of understanding it may as well have been.
Yes, old stun was obnoxious, and didn't provide much counter play. But you still had a cast time, and you could itemize against it, or even "predict" it the same way OP want us to predict enemy moves when we land the new stun.
Anyway, I was fine with it being nerfed. But why like that ? Tons of suggestion have been made everywhere on the boards to rework it so that you can still land W, or use it defensively. I would be fine with a reduced stun duration too, no need for 2.5s. But this delay is just too much.
You can't land W any more, and you can barely save yourself once every 15s. That, and people don't get that having an enemy in the cage is still dangerous. Syndra, Viktor or Annie will delete you, trapped or not...
It's usefulness in teamfights really hasn't been changed too much as people will still get hit by it in the chaos of abilities being used and hitting the back line with it is just as difficult as ever.
It did change. Now you will get someone, but you don't know who. You're still waiting for the enemy to make a mistake. Zoning is still as great, thought.
The nerf to R ratio I cannot dispute as it may have been a little much. Sorta just limits the targets you can use it on to exclusively the enemy's AP carry or another squishy.
Because "Just farm twice as much with your new Q spell, even if there is the same number of minions as before". You can't really catch up the ratio nerf with new Q. You could farm nearly as much with the old one, it's just that it was used to poke.