How could Saving Mr. Banks be anything but a home run? The story of a beloved movie musical, featuring a beloved actor portraying a beloved entertainment icon would appear to be a slam dunk, no? Oh, and most of the movie is set in a place that almost all Americans of a certain age have visited or fantasized about visiting.

Sorry to report that Saving Mr. Banks is not a good as one might have expected. The making of Mary Poppins with Tom Hanks as Walt Disney, set at Disneyland is a tedious story that could have benefited from a more streamlined script. The movie brings some big fun but also is overloaded with the dour disposition of author P.L. Travers (Emma Thompson). Walt’s best efforts to charm Travers into letting him make Mary Poppins into a Disney movie are met with strong opposition.

A movie that initially promises light-hearted fun adds in an overly long backstory that reveals why Travers is the way she is. Not that the fun stuff isn’t fun—much of it is. The songwriters Richard and Robert Sherman (Jason Schwartzman and B.J. Novak) provide many of the film’s highlights. Travers seems to be slowly warming to the efforts of everybody on the Disney team, including her driver Ralph (Paul Giamatti), only to bolt back to London without agreeing to sell the rights to her beloved book Mary Poppins.

The back story, featuring Colin Farrell as her alcoholic father, is set in century-ago Australia. The flashbacks show us the real life inspiration for Mary Poppins, amid circumstances that are definitely not light-hearted.

Eventually, Disney travels to London in a final effort to close the deal. In the climax of Saving Mr. Banks, Disney tries to relate to Travers on a more personal basis. It’s a touching scene and audience tears will be shed.

We know going in, of course, that the film Mary Poppins was made. It was made the way Walt and his team wanted it made. Saving Mr. Banks serves as an excellent promotional tool for the 50^th anniversary of Mary Poppins. SMB adds to the legend of Walt Disney and is likely to increase awareness of Walt among younger generations. (There’s plenty of longtime love for the man among boomers.)

Saving Mr. Banks will likely earn Emma Thompson a best actress nomination. She’s great in a mostly unsympathetic role. And, because the industry loves movies about movies, don’t be surprised to see SMB get a best picture nod. Just don’t go to your theater expecting movie magic. It’s a solid film, but it could’ve been much better.