That being the case, there IS a need for a 'Standard' Human for the Klingon Defence Force.
I'd argue it's a case for removing the human parts from aliengen.
While a klingon Fed is somewhat reasonable due to the multicultural open door nature of the Federation, the KDF is much less... forgiving... of it's enemies. Even if a human did manage to join the KDF the moment the war was on, assuming they weren't executed immediately, I have trouble believing they'd end up anywhere nicer than Rura Penthe, never mind in command of a klingon starship...
I was going to say that at first as well, but since Federation players can get Klingon faction BOs from the Diplomatic Corps that's obviously not an acceptable excuse. Hopefully whenever there's a KDF equivalent of the Diplomacy system, that might work to alleviate the problem.
A Human BOff I could potentially see. A Human KDF captain, on the other hand...not so likely, especially in the current astro-political climate. As pointed out above, the Federation is more tolerant of it's "enemies". The Klingons would most likely shoot on sight...or tort...um, interrogate them for sensitive Starfleet secrets.
Klingons can tolerate humans. Ferengi are too much like Romulans: always scheming, but for Ferengi scheming to make money. And Ferengi have no honor: they'll cheat their father, brother, best friend, etc if there's a buck to be made. Cheating is expected in the Ferengi culture.
It is neither and both at the same time. It has many sides yet it has none at all. The statistic follows the non-Euclidean arithmetic formulas. Either that or it's just a prime example that 36% of all statistics are made up on the spot. Five out of four statisticians will agree with me on that.