Well it's not like TOS was a science heavy show. It was a science fiction show, using fictional science as a backdrop for episodes. It was also a product of its time. Special effects were still crude even by 80's standards and budget reasons made certain things like props or alien worlds look fake ...

The fact that TOS was basically building the setting willy-nilly from episode to episode? I suppoose, at the time they were not expecting it to go anywhere. If i remember right, Gene Rodenberry did say in an interview he was very surprised with the popularity of Star Trek and it was also the sixtie...

I do believe it was, he is on the cast list anyhow.

*From the mists, an new member pokes his head out and draws a deep breath* Agreed, the TOS concept of distance was shakier than a rubber bicycle. Even in later series, distance was not taken seriously. Remeber the ship of cadets in DS9? they were supposed to be circumnavigating federation territory ...