Just finished Crisis on Centaurus. I'm reminded both of why I thought it was worth revisiting and why I sold off my original copy. It has some elements that are quite creative, particularly the depiction of the accident that befalls the Enterprise, and I quite liked the role the ship played in the climax. But the depiction of Centaurus and its society always bugged me for how identical it was to 20th-century America, right down to gasoline-powered cars and brand names like American Express, Baggies, and Sears Roebuck (which doesn't even really call itself that anymore). It's so oddly unfuturistic that as I was rereading it, I wondered if maybe Ferguson had initially written parts of it as a contemporary thriller and then reworked it into a Trek story -- maybe adding the damage to the Enterprise in order to explain the lack of transporters and easy communications and the like. Although there's nothing in his Voyages of the Imagination interview to suggest that. And come to think of it, his portrayal of 23rd-century Earth in A Flag Full of Stars was just as unfuturistic, and I didn't care for it there either.
I'm also surprised by how small a role Joanna McCoy had in the novel, despite being on the cover. My memory of this was as her big featured story in Trek Lit, but she was very much a peripheral character; she had considerably more to do in her two Marvel comic appearances (as did her counterpart/"sister" Barbara in Gold Key's Trek comics).