Kay Anderson's coverage of SFS in CFQ (and in a slightly different form in THE MAKING OF THE TREK FILMS) more than implies that Paramount cleared the decks after TWOK because of the rampant theft of property and all the leaks to outsiders. As far as I know, the situation did not improve substantially, since costumes seem to have gotten stolen all the time during that whole era of TOSflicks, plus on SFS you had inferior work with the new folks. SFS is when they started doing stuff like coding the scripts so they could be traced back to the party who got that particular one, so it sounds like they were really serious about cracking down.
Minor seemed a little bitter about not being asked back ... y'know, come up with the terraforming idea and to use the nebula as a tactic, then find yourself gone. Robert Fletcher carried on through the first 4, but outside of Doug Wise (who may have been a mandatory hire, though even he missed SFS, the only TOS film he didn't do), there wasn't a lot of continuity of personnel that I know of past TWOK.