Isn't the script writer, or it might be the director, for PotC3 different to the one who did PotC2?
I don't know and don't care.
The movie is getting really bad reviews, but honestly, most of the people saying they didn't like it also didn't like the first two. I've heard so many things that make no sense at all to me, like "you feel no sense of danger for the characters" and shit like that.