So did Arnold actually have any professional training to be doing any of this stuff? Because it sounds like he was literally some dude off the street who happened to be friends with Rodenberry, and was just handed the job.
I have to wonder if perhaps they wouldn't have been better off with someone with some kind of literary/creative analysis training.
RA wasn't the only port of call re the tie-ins. He was
reading things so that GR didn't have to read the whole thing himself. GR was simply too busy. Media tie-ins are bought and read by 2% of the general audience.
We know he did the vetting of tie-in manuscripts after Susan Sackett and others got too busy to do it. Susan is a professional writer, but she wasn't when started off in Trek - as GR's
secretary, with a teaching degree behind her.
The proposals and manuscripts were already being examined by the licensees' editors
and the representative of then-Paramount/Viacom Consumer Products. RA didn't have to be creative, just advise on problems he perceived. (He made some enemies doing that, certainly, but it was a group of angry writers and supporters who started publishing quotes from his memos on the Usenet and GEnie electronic bulletin boards. Normally, fans wouldn't have been privvy to such internal information.) I believe RA also looked at the scripts and Paramount's media releases, and again found many, many errors that others didn't.
Margaret Clark and Paula Block started out as Star Trek fans too, you know. I assume they've had training as editors, but perhaps not. Many, many professionals playing in the Trek sandbox - writers, actors, makeup artists, SPFX people, etc - got their start as
enthusiastic, amateur fans who were in the right place at the right time, or knew someone who knew someone.