The problem with Veigar isn't his E, it's his W+R+Q

Were the changes to his E a nerf? Yes. Yes they were. All of his changes were nerfs.

But disregarding that -- You can still land his E. His E actually offers a little bit of strategic play now -- you can use it to zone people. Would it be nice if the cast time were removed in lieu of the activation time? Yes, yes it would. Would it be nice if it did a minuscule amount of damage on activation in order to pop Banshee's? Yes, that would be nice too since it's so easy to avoid now. But that's not the point. It's still possible to land it, it can be used to play zoning games. E is not the problem.

His W was nerfed as well. With the timer on it, until E is at max rank you will never, ever land it. It might as well have been changed to only damage minions - that would have accomplished the same thing. I guess you could play zoning games with it, but...wasn't Veigar meant to be a burst mage?

His R ratio nerf doesn't look like it hurts too much. But-- Even if W lands, he simply doesn't have the damage to kill people with his full combo until late, late game when he has a nearly full build and has spent a lot of time stacking his Q. How often do games even reach that point? Not often at all.

His Q, speaking of stacks, is actually easier to farm with early on. Except this is decidedly unfun - because now he's a passive lane. Good luck landing it where you need to in the massive minion hordes that stack up late game (or even having it up often enough to take advantage of those hordes for the purpose of Q stacking), let alone landing it on your target in the middle of a teamfight. The pierce-through on Q hurts his already weak early game more than it helps: Veigar is now forced to push the lane in order to harass, or even just take that cannon minion.