There is probably a lot of confusion about what a film producer actually does. Some are very hands on, others almost never visit the set.
Replacing a director(s) this late in production is almost unprecedented. That this is a troubled production is not just in the eyes of fans, but the industry as well. This could seriously dent the career of a younger less experienced producer.
While it is highly unusual, it is hardly unprecedented. It has happened many times. Sometimes leading to unsalvagable results, but often (and the other Disney films that this has happened to in the past decade fall in this second category) they result in a resounding success. The classics Gone With The Wind, Wizard of Oz, and Spartacus are just a few, as are Toy Story 2, and Brave. And usually it is the director who gets replaced whose career suffers, not the producer.