I bought the Limited Edition of Halo 4 and I had access to the 8 specializations at first but right now I only see Wetwork, Operator and Engineer which I’m currently have active.
They come and go, check again later they will probably appear back again.
Restart the console, works for me. Waypoint loves doing whatever the hell it wants, not what it SHOULD be doing. I keep losing all the armour as well as specialisations, at least until I restart.