I listen to it in Audio and there was an interview of Chabon at the end(maybe the same Funhouse?)He says(?) that the original title was "Jewish with swords" ,finding the idea of a menacing jew funny.
Mostly it found it too foreseeable(an ugly English word here) and short,it lack panache which is escential in the genre.It was as if he liked the idea but was bored by execution.
The abyssinian by Jean christophe Ruffin is much better in similar settings and period.
Amazon.com: The Abyssinian: A Novel: Jean-Christophe Rufin: Books