Originally Posted by
Noctiphobia
It's weaker than assassination and you can't just go and do your PvE rotation on healer. Smoke bomb is no longer exclusive to subtlety, so the only advantage you have in terms of utility is more frequent cheap shot through shadow dance (while assassination gets garrote and healing reduction, and outlaw gets gouge and 1.5 min blind which makes it not line up with enemy trinket anymore).
But on the other hand, if you're not aiming for R1, almost everything can work. I'm playing shadow priest in 2v2 myself at ~2100, and I met literally only one other shadow priest in 2v2 during this expansion. And I don't feel like my spec is holding me back too much. I still sometimes see ridiculous things like 2x fire mages. I doubt 3v3 is different in this regard.