I've just finished reading Saul Bellow's Humboldt's Gift and, in reading the reviews afterwards, discovered that it's a roman à clef (which has been defined as "a novel about real life, overlaid with a façade of fiction"), with the narrator based on Bellow himself and the character Von Humboldt Fleisher based on Bellow's friend and mentor, the poet Delmore Schwartz.
The novel has given me a useful angle on how I might approach either of two ideas for a novel I've been kicking around, each of which could borrow heavily from my real-life experience. I'd previously considered taking pains to change the details of characters and events so that no real person could be identified, but after reading Humboldt's Gift I'm attracted to the idea of making a couple of the principal characters more transparently recognisable.
However, I'm concerned about the risk of being sued for defamation if the real-life person recognises themself in the novel and is unhappy with how they're treated.
Are publishers less likely to be interested in the roman à clef because of that risk, especially if the author is (currently) unknown?