I was just reading a review earlier today that said they were concerned about the same thing, but only waited 10-15 minutes or so. I'll look for the link reply again. One thing to keep in mind, many people want to be the first ones off the ship. If you're just walking around the ports, you may want to consider waiting a little until the crowds diminish. They you might be able to walk right off without any lines!
Princess has a way of creating smaller spaces within a larger room and it does lessen the crowded feel. I would guess that one of the worst areas on that ship for crowds is the photo gallery area, which on most of the Princess ships I've been on is generally in a hallway between the atrium and back of the ship.
I had doubts about this ship too, but have since read enough good things that I'm willing to give it a try. It will probably be our next cruise!
I'll go look for that review and post the link.