The action-adventure ones would obviously translate more easily to TOS. Three come immediately to mind for me Lonely Among Us
, Where Silence Has Lease
and The Ensigns of Command
Of course, Lonely...
already has some TOS elements with the battling delegates being ferried to a diplomatic conference.
As an aside, I always thought the Voyager episode The Thaw
would've made a great TOS episode.
How would that work, without the holographic technology of the Doctor?
I've always thought that the Voyager episode "Riddles" would have made an excellent episode of Classic Trek.