Star Trek Online do them justice. Understandably, when Cryptic made the announcement that Klingons would be primarily a PvP focused faction, people were concerned. Players don't want their beloved gruff 'n tough warrior race to become a second-tier faction.
My time with the Klingon side of Star Trek Online has given me a pretty good sense for what Cryptic is trying to do with the game. It's not exactly what you may be thinking. It's most certainly not anything like Lord of the Rings Online's PvMP, as the Klingons have a substantial chunk of the galaxy map to themselves.