Let be honest and look at things objectively. Dstahl has said repeatedly they want to complete the KDF before adding any new factions. Discounting that statement for a moment, let look at what would be required for a true 3rd faction. They would have to add tech to the engine to allow that sort of thing. Next they would have add dupilcated to the faction specifc fleet actions. Next they would have to revamp all of the cross faction content. In addition to that they would creating a new tutorial and enough PvE content to take a new faction to level 50. That sounds like a mega-update like Season 8 is purported to be. But they would leave the KDF in the lurch and no new content for the rest of the players.
So I really don't thing that a new Romulan faction is coming. Now back to Dstahl's repeated statements about now creating a new faction until the KDF is complete, and his statements about personally pushing for a complete KDF inside of the company. So what I think mega-update of Season 8 (which will be going back to regular Updates for a while) will be is the completion of the KDF. They have the added personal to do this. Now lets look at what they need for this.
1) Tutorial - This will carry a KDF character to level 4 or 5.
2) Level 5-20 Content (assuming that currnet content levels don't change)
What would be good for these levels? Well the equivalent Fed levels are dealing with the KDF. A lot of content can be created telling the KDF side of things.
a) Tracing an evidence trail of Undine infiltrators which leads an a high ranking Federation Ambassaor. And then leading to a hidden KDF listneing output which your have to fortify incase teh Feds come calling.
b) Then getting involved with B'Vat and helping him in his plots. Trying to kidnap the Kuvah'Mag from a peace conference. Tracking a supposed traitor down to a trading station. Find the hidding place of the second Doomday Machine and bringing it back to KDF space. Getting involved with a new weapons development program. Dealing with a gene agumentation program be B'Vat's pet mad scientiists Amar Singh.
c) Kidnapping the Miral Paris successfully this time. Taking her back into time to have the shameful era of ridgeless Klingons undone.
d) Taming and discovering the secrets of controlling the Doomsday Machine.
All lots of other good stuff.
3) My musing are tapped out at this point. But we need enough upper level content to get a KDF player over the humps in the 20+ level content. It need to be KDF specific content. Preferably some inside of KDF space and others in the various other fronts (i.e Romulan, Carsassian, etc).
Edit: And as to the Raptor's Wings. I'm guessing it's a Romulan based Featured Episode with the epic awesomness was are accustom to. Since DShathl has said that Denise Crosby will be returning to Cryptic for more (I assume) voice over work. It can only be centered around the fate and return of Sela (and maybe, hopefully, the history of Sela and her mother as well).