Mary Cas, you make great points about Andrew. He was able to get to work in Rome, but only with the intervention of a mob boss. He's supposed to be of "the pure faith" according to Michael, but I doubt it. If he were, he would have disassociated himself with the Corleones and even his father's legacy. Andrew is not so pure. Having Tom Hagen in the movie might have developed this more and Duvall was greatly missed.