Ralph Senensky directed episodes of Star Trek, Kraft Suspense Theatre and many other shows. He has commented recently on Star Trek's legacy and compared it to that of his other work:
STAR TREK was indeed a phenomenon. I directed six and a half episodes of the original series. I would guess (and I’m sure my guess is very close to being accurate) that I worked a total of ninety days on the series. I worked more days than that on just the pilot of DYNASTY. I directed twice as many episodes of THE WALTONS and two and half times as many episodes of THE FBI; I directed more episodes of THE PARTRIDGE FAMILY and more episodes of THE COURTSHIP OF EDDIE’S FATHER than I did of STAR TREK. And yet today if you google-search my name on the internet, you will think I spent most of my career directing STAR TREK. As I said, STAR TREK was indeed a phenomenon.
As I have written before, Star Trek did not enjoy success during the 1960's. Yet its legacy exceeds that of the more popular shows of that era. Senenky's quote above is but one indicator of that relative legacy.
I will not explore all of the factors that made Star Trek successful only after its first run ended. That is a subject for another blog. But the fan base that has grown around Star Trek clearly has reason to be interested in KST. The overlap between Star Trek and KST exists not only with the actors, but with writers, directors, plots and miscellaneous program information. Star Trek fans would undoubtedly enjoy seeing their Star Trek heroes in other roles, especially where multiple such characters appear in the same episode. I believe this because (1) I enjoy seeing the Star Trek actors in KST roles myself and (2) memory-alpha.org often focuses on non-Star Trek shows where Star Trek actors appeared together. By not being aware of KST, Star Trek fans do not know what they are missing.
I have always regretted that Star Trek ran for only three seasons. I never really enjoyed the spinoffs. Episodes of KST and other contemporary shows seem closer to the old Star Trek than do the recent Star Trek spinoffs. My own experience with KST (and other shows) indicates to me that it was not so much the science fiction that I liked about Star Trek, but the stories. KST provides the kind of plots (plus the actors) that come closer to replacing Star Trek than anything else I have found.