^ Vonda McIntyre's novelisations of II and III were very good, with lots of extra character development and scenes.
Totally agreed. Amazingly good!
Once she left the series, I don't think subsequent novelisations were as developed.
Friends and I noted, at the time, that Vonda's novelization of ST IV
begins to add new material as she had on the previous two, but abruptly becomes a strict conversion-of-script-into-prose from just after the 20th century trash collectors were revealed to be brainstorming cliché
d lines for a movie script they're writing together.
From comments in "Voyages of Imagination", it seems like ST IV might
have been the first tie-in manuscript scrutinized by Richard Arnold, rather than Susan Sackett, with objections to authors adding new material. Certainly, Vonda's experiences getting "Enterprise: The First Adventure" and ST IV through the approval process seem to have turned her off ST tie-ins.