I had a thought today. Lets say that the TOS had received the proper fan base that it enjoys now back when it was originally airing, to the point that they created spin offs like they did for the TNG. What concept or episodes would have made for good spin off material?
I understand that spin off's were not common in the 1960's but just humor me. DS9 played heavy on the Borg and Cardassian occupation episodes of TNG, as did Voyager to a lesser degree. Was there any reoccurring characters or overarching plots that they kept coming back to?
One that came to mind was the border dispute between the Klingons and Federation, perhaps taking place on K-7. The show being like DS9?