The movie is worthy enough to be an Indiana Jones film, but it certainly doesn’t add anything to the canon.  Most of the non-Harrison Ford characters are superfluous, but that’s always been the case (save for Sean Connery, of course).  So yeah, it does sorta feel like a blatant cash grab.  But one of the reasons for the success of the Indiana Jones franchise is its sense of fun, and that’s retained in this installment.  Yeah, some parts are ridiculous, silly, unnecessary, or slow, but there’s enough fun stuff to keep things moving along.  Oh, and while no one may be positive about the origins of Indiana Jones, I see no reason to believe anything other than the theory he was based on a University of Chicago professor.