1356, I admitted to not realizing until later that it was the fourth book in Cornwell's Grail Quest series - and I hadn't yet read the earlier three. That totally screwed up my main pleasure in reading a series of novels so long after the first was published - going from one to the next without waiting years for its publication.
Water under the bridge - despite knowing the end of the story (never a major concern with historical novels), I did go back and read the earlier installments in the Thomas of Hookton saga: The Archer's Tale (aka Harlequin in some editions), Vagabond, and Heretic. These three suffer from the same fictional strengths and historical weaknesses as 1356 - they're generally lighter on recorded historical events and persons than many other Cornwell novels.
For that reason, the 5 criteria will look pretty similar. More significant at this time is a change to the criteria themselves. It has occurred to me that many historical novels do a fine job of presenting historical events and characters, but fail to create believable personalities for the fictionalized versions of those characters , or to give them plausible motivations for their actions.
Creating believable characters is probably the hardest thing to do in any form of fiction, so I can't be too hard on historical novelists. In one way, they get a head start - historical characters have at least some events of their lives recorded. The novelist can approach the character's personality as a detective might, construction plausible motivation from a series of actions.
Other novelists take a different approach, creating entirely fictional characters like Thomas of Hookton, who inhabit the chosen historical setting. Fictional characters can run in well-greased fiction personality grooves, making them instantly familiar to readers but ultimately less satisfying. So, for instance, we know Thomas of Hookton will never give up The Quest, because he's a man of honor, and men of honor never give up (in novels).
These thought about believable characters and plausible plots led me to revise the 5 criteria. I dropped #5 - "Would I read another novel by this author, continuing in this historical period, with these characters (or new ones)?" I don't bother to write about a book if I didn't enjoy it enough to read another by the same author, so the question answers itself.
The new #5 is "Were the fictional or fictionalized plot and character motivations plausible?" Plausible is perhaps a lower bar than believable but is, I think, the minimum standard necessary to ensure reader satisfaction. As indicated above, although I enjoyed Thomas as a character, some of his characteristics and actions are plausible only within the well-known and established framework of "man of honor" and "mythic hero" archetypes.
So, the revised 5 criteria will debut next time, and we'll see how it works out.