Still wondering how you should be playing the new Vel'Koz? Try tank.
Sounds crazy, I know.. but since they overloaded everything into his passive and ult, you can successfully build tank and still achieve the damage you're used to as Vel'koz, and you don't have to risk death every time you go in to combo someone. And since you're all true damage, you don't have to worry with many damage focused items.
and your boot of choice.
You may ask yourself why Visage? I take it mainly for the health and CDR but the Ocean's Drake passive is enhanced by it as well. You may be skeptical, but try it out.