Mickey Rooney was the first actor considered to play the human sidekick of Francis the talking mule, but the role went instead to his friend Donald O'Connor. Six years and six mule movies later, O'Connor decided to move on to greener pastures, and workhorse Rooney was brought in to close out the series.
This movie -- without O'Connor and without Chill Wills doing the mule's voice -- gets no respect from critics and die-hard "Francis" fans. Admittedly it's not as funny as the early "Francis" films, but Rooney and Paul Frees (as the voice) give it their all, and the movie is perfect for children.
The fact is that the "Francis" series was running out of steam already. Winding it up with another military comedy would have been the coward's way out. This movie is more like a harbinger of the "Scooby-do" cartoons: Cops and robbers and alleged ghosts in a completely non-threatening environment. No adult content to trouble parents.
Could it be better? Yes. But it fills a certain niche very well.