The only thing I can think of improving for a potential second edition would be to commission artwork rather than licensing pre-existing artwork. The artwork used is very high quality, but something about it just screams 'obviously not made for this book', probably the wide variety of artists (that's a huge credits block!) and lack of a cohesive theme.
Maybe grab two or three artists and commission the art yourselves next time.
Otherwise, I'm shocked more people don't know about this.