I think the key is the distinction between being light on content/elements and being light on those things and having much of it being ill conceived and poorly implemented. I don't object so much to Klingons not having the same volume of PvE as the Feds, though I think at a minimum an MMO should have at least two complete factions especially when the main faction has only one content path for all its classes/players. What gets me is that even shorting Klingons on PvE the PvP stuff is so terrible, and so poorly conceived at that.
When you consider the Klingon state of things STO is simply a game with one bit of content (the Fed stuff) where most MMOs have exponentially more content. And that being the case, it is all the more reason to be shocked at how poorly the Klingon side of things is. Even if they didn't manage to get Klingon PvE on par with the Feds how could they go to live with the psuedo content of PvP so poorly implemented?