Yeah, skoffs and BM pretty much nailed it. If you're taking it to do damage, outside of fighting horde armies, don't expect it to do much.
If you can manage to pair it up in a list where Orikan and the C'Tan are contributing in other ways, and the terrain shenanigans are just icing on the cake, then it's potentially pretty good. Orikan's reinforcement thing can be pretty awesome for a Flyer heavy lists and saves you on the
ADL, and C'Tan can be effective if you keep them alive.
I would say don't try it till at least 1500, maybe more. Monolith seems like a good pairing with this though. Could use Orikan's reinforcement buff to come in pretty easily turn 2, and then bring the C'Tan up to party through the portal. Also, the opponent might respond to the
WW shenagins by clumping up a bit and staying still. The Mono could then take advantage of this with some 8/3 pie plate goodness.
Other units that seem to be good in a list like that would be
LG. Good place for Orikan to hide, and
LG would love taking advantage of the opponents gimped movement.
Historically (in 5th) people paired
WW with scarab farm. Then you have 4+
MCs, a bunch of scarabs storming down the field to take advantage of slowed units. Not an awful build.
I can't remember, would all of Orikan's abilities work if he was not deployed first turn but was rather in a Night Scythe?
Edit: Originally wrote "customer" instead of "opponent." Heh, that's what I get for trying to post in between tickets at work.