Veigar's rework

I was expecting a lot from this rework as a veigar fan.

The ult changement is understantable. It was really lacking counterplay (hello you have loose 300HP -> you're dead). But, the interest of veigar was to easily nuke someone, if you need to combo someone it's just like other mage. But maybe with new ap Q/R will still be enough to kill someone in late game. (Q is faster so it's can work) I'm not fond of this changement but why not (and having nuke healhy for the game is quite a challenge).

I would like to know if veigar clearly stacking better than live, or if the lost of mana regen (passive and item) penalize him too much especially in early game.