Zoroak doesnt have any priority moves it can abuse with its great offensive stats. I believe this pokemon really resembles Lucario, although boasting more superior offensive stats. With now priority moves, Zoroak will probably move to BL as one hit from pretty much anything from any pokemon will K.O. it.
Possible roles:
Lead: Zoroak fails at this position. Most leads in the metagame have a priority move, so even if zoroak is sashed, it will still die.
SD: Zoroak can abuse this role pretty well due to high speed and offensive stats. However, being very susceptible to priority moves, it wont do pretty good
Choice
[scarf] : May work
[specs] might
[cb] meh.... should work in theory
The point of leading with Zoroark would be to mess with your opponent's head. It's certainly not the best at setting up team support then getting out fast, but it can trip your opponent up by making them think their lead is inadequate. Zoroark's mind-gaming capability alone should make him a fair candidate for OU. That is, if the "it shows the opponent your team" thing only applies to random online matches...