I doubt that the Romulans will become a playable faction so soon--the devs did imply that such a thing wasn't going to happen before Season 9 goes live at the earliest. However, a large expansion to the New Romulus story may be likely--perhaps we need to fight off an attempt by Sela's remaining supporters to conquer the planet or such.
How many Starfleet Engineers does it take to exchange an Anti-positronic Photon Emitter?
"March Beneath the Raptor's Wings" to me implies that it is OUR chance to owe allegiance to the 'raptor's wings', i.e., the symbol of the Romulan Star Empire. It's like saying "March beneath Old Glory." I think that phrase would have a pretty clear meaning.
To me it seems to be a clear hint at a Romulan faction, and if that's NOT what it is, then shame on Cryptic for breaking my poor little heart.