The most frequent rumor that I tend to believe is for the Dark Kingdom park. It's just a matter of when they decide to go forward on it. However, I'd also love a DisneySea clone.
Our resident insiders such as Lee have confirmed that Disney has no plans whatsoever to build another WDW park. They've got enough on their plate as it is. I also recall him saying they scrapped the Dark Kingdom plans a rather long time ago, before they stopped thinking about new parks altogether. So no, 5th gate isn't at all in the cards.
@mrg1106
From what you're saying, i doubt you've been on many of the attractions you're listing before they were redone considerably.
- Backlot Tour at one point used to have a more extensive look at the costume department IIRC as well as went through a small town of house facades used in TV shows and other stuff. It's heavily stripped down. Not sure when this stripping down happened, but it was far superior in the mid 90's. It has changed rather drastically.
- Spaceship Earth lost its communications theme in favor of just "history of man" basically. They also dissected and removed what little we had of an ending descent sequence and replaced the props with dark tarps (adding in that corny and badly done cartoon thing).
- Universe of Energy just needs to be redone completely with the same theme of energy. But it needs to be modernized and given the proper respect. I'd bring back that awesome song as well.
- The Indy stunt show is just old and needs updating or replacing. Assuming they can do something better than the original and not make it worse. A version of the Indy ride from CA would be great.
- Space Mountain was a terrible refurb. Whilst Disneyland's got a really loving refurb which completely replaced the entire track and made numerous changes to the sound system among many other things, almost nothing was changed about WDW's ride (very little of the track was replaced at all). The interactive queue is just tacked on terribly (unlike Pooh's, which is amazing in comparison).
Interactive queues are hit or miss. Good idea in concept, but they're destined to fail when uncontrollable and ill-disciplined kids are involved. In terms of concept, there's even a good and bad way to do it. The way it's done in Pooh and (IMO at least) Haunted Mansion are the right way to do it. The way it's done in Space Mountain and Soarin' with basic video monitors tacked on in a quick and cheap way is not the right way. Krack does have a very valid point though about interactivity being something that can't be maintained- building something that kids touch (or rather, beat up on) all the time is just asking to have it broken. It's an even bigger disaster when coupled with WDW's notoriously terrible management.
WDW and Disneyland are definitely not equal.