I've already seen numerous posts here on Tribble forums regarding Romulan D7 Battlecruiser being added to the game, with one idea being making it a reward for Temporal Ambassador mission (which currently rewards Romulans with either Ambassador or Kamarag, depending on the alliance).
Now, with Cryptic's recent switch from earlier plans about Romulans flying their allies ships it would seem that the only non-lockbox vessels the faction can use at endgame are the Warbirds (all 5 of them...), with only T1-T4 dilithium or C-Store ships being cross-faction. This also means that their overall choice of gameplay and strategy is quite limited and that they can only fly ships that use Singularity mechanic.
So, to introduce at least some variety, how about that D7 Battlecruiser being basically a re-skinned K'Tinga, only with Kamarag's stats? This could not only allow players some more flexibility and alternative, but would also fit the game in terms of canon, as these ships were basically an old Klingon design to begin with (thus they wouldn't use Singularity Warp Cores).
The ship itself could just be an existing K'Tinga model, only with that gray material Tier 1 T'liss is using. Not sure how much actuall work would be required for such a (pressumably) minor change/addition, but personally I see this as a great opportunity, especially if a T3 version of this ship could be a reward for Temporal Ambassador, with T5 variant being introduced to the Fleet Store, like Ambassador and Kamarag.