I think that some people are missing the point about Klingon culture being one dimensional - you have STILL have a culture that symbolizes something general - without them being written foolishly.
The two are completely separate.
Take House, as an example, a show which being episodic, is very similar to Star Trek. Most episodes explore philosophical concepts of some kind or another. Not every American who appears is wearing an Abe Lincoln hat, whilst eating a beef burger, and carrying a Winchester - but they are still used to convey whatever concept-of-the-week is needed; one might be a bigot, one might be a hypocrite, one might be exploitative, one might be altruistic.
There is no reason why Klingons can't symbolise a decaying society (TNG), or a military republic (TOS), or colonialism (ENT) - without all of them talking in that same ridiculous way, and opening a barrel of blood-wine or some other crap to remind us every five seconds that they are Klingon (something that is patently obvious, and does not need stating).