It would have been nice to have Arex and M'Ress stick around
Well, we'd come out of the Richard Arnold era. He had insisted they be removed from Peter David's DC Comics TOS Series II storylines and the characters were put into limbo.
A few years later, John Ordover suggested to PAD that, now that RA was gone, Arex and M'Ress would be quite at home in "New Frontier". Had PAD been writing a TOS era series of novels, I'm sure he'd have been making use of Arex and M'Ress, but he seized the opportunity to use them again. It wasn't as if other authors had clamoured to use them themselves.
We are "getting to know them in the novels": "New Frontier" novels.so we could get to know them better in the novels.
For the longest time, TOS novelists had many chances to use Arex and M'Ress associating with TOS cast members. But they didn't. Thank goodness for the snippets throughout Alan Dean Foster's "ST Logs". Arex and M'Ress got a very brief cameo in "The Galactic Whirlpool" by David Gerrold. Arex got a briefer name drop in "Time for Yesterday", thanks to AC Crispin. M'Ress probably should have been in "Uhura's Song", but Janet Kagan had never watched TAS.
It seemed that it was only after PAD started using them in NF that other authors' interests were piqued: "Mirror Eyes" in "Tales of the Dominion War"; "Ex Machina"; and "Crucible: Spock: The Fire and the Rose".