I think the splash area is a given at this point. It's convenient, and has been a hit on the Wonder. I don't see a reason why they wouldn't put it on the Magic.
I've heard that they'll be doing a lot of engine maintenance and fixing of the exterior of the ship from the PC crossings. I've also heard that all of the carpet on the ship will be replaced, and I've heard those rumors about flatscreen TV's and updating Animator's Palate.
I can't wait to find out what they're actually doing!