I think that Dana Barrett didn't really have a place in GBII. However, Sigourney Weaver is such a good actress that she could pretty much read the phone book and make a good movie. After all, she used to shoot aliens. What might have helped this position is if Dana were to strap on a Proton Pack. And maybe even have a ghost pop out of her chest at the end. I don't know. Maybe that last part was a little too far, but Dana could've put on a pack and joined the guys. It would've been cool!