Vel'koz needs a compensation buff.

Taken from Barph, Master Tier Vel'koz main:

His main combo went from EWQR + 3 passive procs to EWQR + 1 passive proc, compensation in the form of +0.4 ratio on the ult and true damage on it. At level 6 thats a massive nerf, taking 2 passive procs off gutted his level 6 where he could previously 100-0 a 30 MR target, he cant do that anymore. Late game its still a nerf against any squishies since velkoz did true dmg to them anyway and to tanks its only better if you got the passive on them first which means the situations you use your ult are now limited more harshly. The ult is extremely underwhelming on its own and no AP ratio buff is going to make up for the 2 lost passive procs(that was 410 damage at 18) Not only has his kit changed but his build has too, with the ratios moved on to his passive/R which ideally are true damage Void Staff loses its appeal on him so Deathcap now should come first in the build, but that just means Ludens has to come last which really hurts his movement speed, Vel'Koz feels so much slower this patch with the loss of alacrity + late ludens.

Overall the changes feel bad. Its definitely a nerf for him overall since his early game is gutted and his late game is only situationally stronger in a few cases but weaker in most practical ones. Only good thing to come from this is seeing the EW+P damage especially late game.

Please consider a buff Riot balance team. He's in a really bad spot right now. In addition, The second part of your w doesn't apply a stack if you begin ulting which certainly shouldn't be the case, I've messed up so many combos that felt second nature prior to the rework because of this. It needs a bugfix/QOL buff.

Thank you for your time.