Interesting note on this, though not...ENTIRELY on topic: He did. As did the entire show, thanks to Gene Coon, who came in as Producer and held that title throughout season 2. Back then, apparently - and I don't know if this is still true or not in Hollywood - they'd get scripts from writers, then go back and forth with comments for a few drafts, then finally 'tweak' it to the show's standards. Early on it was Roddenberry himself who did it mostly, even over top of the guy who was SUPPOSED to do it - John Black, the first producer, who left midway through season one. But it was turned over to Coon later on. He wrote a few episodes, and rewrote/polished a bunch more. Coon was the one responsible for most of what we think of as the lighthearted side of TOS - the witty back-and-forth between Spock and McCoy, Kirk's humor. Roddenberry hated it, and wanted it more serious, and that's why Coon was fired and replaced for season 3 (although I think a couple of his scripts still got produced that year - He didn't seem to harbor too much of a grudge). Frankly, I'm not sure if I'd be much of a TOS fan without him - he made the show what it was, made the characters who we know them to be.
I'd highly recommend reading the three-volume "These Are The Voyages" books by Marc Cushman which cover each of the seasons behind-the-scenes in great detail, if you're interested in that sort of thing. How the show got made - the crazy rewrites and turmoil, and the tonal shifts onscreen, make a lot more sense afterwards. I don't agree with his central premise - that Star Trek was way more popular first-run than we give it credit for - which just makes no sense considering how it was treated by NBC, but the general facts and interviews, production notes, and details are pretty amazing. It's a great read.
And on topic - I've been petitioning Nanjin for a Green Tunic since day 1 (which I'm sure he'll attest to). I hope it gets made...for me, that's how I remember Captain Kirk in most of my favorite episodes.