Here's an ignorant question; how sure can we be about writing credits? It seems to me that the actual credits can differ greatly from the official credits for writing - screenplays or teleplays is what I'm referring to. The City On The Edge Of Forever is an obvious example.
Also, was Gene Roddenberry's work ever 'touched-up' by others, such as Dorothy Fontana? These kind of questions muddy my opinion of his writing ability - I just don't know enough about it. He might have been great, good, fair, or poor; it kind of depends on how much was his, and how much was not. And even when a credit is his alone, there have been rumors about a ghost writer, The Motion Picture novelization as an example. I just don't know . . .