Wasn't the plot about Scotty's family kind of left dangling at the end of the book?
Too often, imo, he was written as just a collection of stereotypes. Scotty dialog is pretty much guaranteed to contain a mention of his engines, booze, Scotland, or >shudder< haggis. I give credit to McIntyre for at least trying to do something with him.
It's kind of funny, but for such a popular character I cant think of very many of the older books that I'd call Scotty-centric. He's got important roles in Twilght's End and The Kobayashi Maru and...I'm drawing a blank.
I love McIntyres expansion of other TOS characters. But thinking of "The Entropy Effect" wasn't Scotty a bit paranoid there. Not at all supportive of Spock when he most needed it. The reasons were valid of course but I suppose I was just a bit disappointed in Scotty there. While I wouldn't say it was OOC I suppose its not the Scotty we know from the movies more like the Scotty from "Operation:Annihilate!" and "Day of the Dove".
Scotty comes across as a sad character in TSFS novelisation alienated from his family but as you say at least we get to see his family.