Now as far as the variants go, I think it takes longer for Klingon ships as Klingon players are pickier on what they like. You can't just add a few angles here and there and expect it to fly. It will take some time. They have already moved faster than most companies.
Heh, then you haven't seen the threads about STO model inaccuracies of the Galaxy, Intrepid, etc. Even after Season 1 update, the Galaxy which was supposed to be "fixed" is still inaccurate.
As far as Klingon ships, they are in the same boat as the Romulans, but not as worse off: There's not been that many classes shown in the movies & TV series.
Bird of Prey - Several types shown and of varying sizes
D7 style - Of which the K'T'Inga falls into. The classic TOS style of KDF ships.
Vor'Cha - From TNG onwards; 2nd most commonly shown KDF ship.
Negv'har - Seen here and there, mostly from DS9.
Raptor - From ENT. Didn't watch the show.
That's it, really. Few types of Klingon warships have been shown on the TV or Movies. Cryptic would probably have to be creative to bring some variety.
And the Romulans are even more worse off as far as canon ships shown on the screen.
Bird of Prey - TOS style, and IIRC, the only Romulan ship type shown in the series.
D'Deridex - Introduced via TNG. Most screen-prolific Romulan ship in all Star Trek.
Scimitar - Introduced and last shown in Nemesis. But a Reman warship.
Valdore - Introduced and last shown in Nemesis.