While the film franchise has brought in billions of dollars for Disney, the last entry, Pirates of the Caribbean: On Stranger Tides, was generally regarded as a miss that was so bad that for a long time it looked like it killed the film series.
The key part of the film’s title that will either succeed or fail at bringing people into the theaters is the first bit, the Pirates of the Caribbean bit.
In the end, the name change is probably not particularly important.
People seem to be willing to give the new entry a shot.