On the OP, after scouting around, I'll throw out the name of Mack Reynolds as a possibility. He wrote the first original Trek novel, Mission to Horatius, that Roddenberry found fault with even after editorial changes. His general works often dealt with the development of utopian societies. Perhaps he felt that he had an advantage in approaching the series because of the strength of how he followed that theme, and the practical implications that showed up in some of his books that mirrored what was seen in Trek, despite the contretemps over Horatius, which was aimed at a juvenile audience. The middle initial D that was referenced, might be accounted for by the fact that Dallas was his actual given name, though he wrote under a number of pseudonyms, a few that used it as well but as a first name, but perhaps it may have been used as the former by some who knew him.
The fact that our resident authors haven't volunteered this author as a guess might indicate there is a glaring and well known fact that precludes its even being in the ballgame, but the connections that are present seem to me to give it a shot.
https://en.wikipedia.org/wiki/Mack_Reynolds
https://en.wikipedia.org/wiki/Mission_to_Horatius
