Keep in mind that the 'network wanted to dumb down the Questor Tapes so I walked away' was GENE's statement on why it didn't get picked up on the show. Given Gene's unfortunate history, it's far more likely that the 'powers that be' didn't want a repeat of 1968 and just said 'screw it'.
It would be interesting to hear the network's side of it (as well as the studio's).
Speaking of Roddenberry's non-Trek writing, the teleplays (often freelance scripts) pre-dating Star Trek have barely been studied. I'd read a book about those projects (especially The Lieutenant; most of what's been written about that series is baloney).