I understand your crossed feelings Jim. On the one hand you want Travers to have more of a say in how her creation is portrayed. On the other hand Mary Poppins is such a freak'n marvelous movie. probably much better than one that Travers would have wanted made. You root for Disney because we know the outcome is great. And it did make Travers rich.
I doubt Travers was as curmudgeonly as depicted or Walt as lovable.