I've seen Pulp Fiction, but not the other two, so perhaps my fear is unfounded. I don't think PF is a good example though, because it can be viewed as a series of short stories in one movie, whereas Watchmen as one overarching narrative (based on what I've heard of Memento, it also has one narrative, but I would assume that the flashbacks fit the story of a man who has short term memory loss). I think those character stories will play havoc with the overall pacing, but just tossing them would be the greater crime.