I was going to post on the apparent pointlessness of the Palmers myself, but I decided to wait until someone else jumped first ;). Edward's visit - yes, there's definitely a purpose to that, both in terms of emotional and narrative plot. The Steele's visit - well, that speaks for itself. But the Palmers? I wouldn't want to forgo such a delightfully depressing couple, but I guess finding out what they're there for will have to wait.