One thing I really enjoy about these early TOS episodes is the greater budget allowed for us to spend a bit of time with crew members other than Kirk, Spock and Bones. I would have liked to keep bumping into the likes of Janice, Riley, DeSalle, Kelowitz, etc in seasons two and three.
Yes, for me this is a definite strength for the early episodes. One of the things I liked about B5, NuBSG, and DS9 was the multi-tiered cast. You get more of a sense of Uhura's and Sulu's characters in the early episodes than most of the rest of the series combined. I would really have enjoyed seeing Riley and Rand reappear for one or two meaty episodes per season.