Boy, Serling really had an axe to grind with TOS...Is this from that grainy 1970 interview over at YouTube?
I don't think Serling had an axe to grind at all. He was merely giving his opinion on STAR TREK, expressing frustration with a series that had so much potential, that could sparkle, as he said, but often fell short. An opinion also expressed by Harlan Ellison as well, who had an actual axe to grind over his own episode.
And while STAR TREK is my first science-fiction love, I don't see it with a haze. It has its faults and cracks. Honestly, THE TWILIGHT ZONE was more consistent in quality than TOS. So was THE OUTER LIMITS.