Except that's not how empires work.
Well, they sorta do: the Romans never stooped to using foreign troops until there was no Rome any more (that is, when various Germanic tribes finally made up 99% of the military, the capital of the "empire" was Milan, Ravenna or some obscure village up north or whatever, depending on the day of the week or whom you asked). And the US empire doesn't fight with foreign troops, either, having burned its fingers a couple of times trying to do so.
The idea of an empire that doesn't allow its subjects to serve in its military makes about as much sense as an empire that doesn't allow its subjects to pay taxes.
You mean Romans again?
The Arne Darvin dilemma always weighed in on my mind whenever I thought about it. It seemed plain to me that if Klingons could at least superficially impersonate humans (less the presence of a medical tricorder or similar scanning device), then at least a portion of the overall Klingon population must be naturally human (or close to it) in appearance.
TOS did not enjoy advanced makeup ot VFX methods or big budgets, but it was trivial to perform futuristic or alien "extreme makeup trickery" nevertheless - shapeshifters could shift and holographic illusions could appear and disappear via simple editing and dialogue means. Making an alien look like human could easily be accepted as another "in-universe trick", a feat achieved by futuristic alien technologies even when it's the cheapest sort of stage magic in our reality.
That would be to the advantage of TOS, really. Whenever the heroes can point to a prop and say "that's a hologram" or mime a bump into an invisible obstacle and shout "a forcefield blocks our way!", it makes the TOS universe seem more interesting, futuristic and alien - even when there's no pressing in-story need for futurism and an object can simply be a physical object, an impassable obstacle can be a solid wall rather than a forcefield, and an alien looking like human can simply come from a species that naturally looks like humans.
That's it. No one goes "those are Klingons."
True enough. Of course, nobody would go "those are Klingons" even if they were, but the door indeed is open to all sorts of interesting alternate interpretations...
Timo Saloniemi