I think they will definitely HAVE to build something after Dino-rama is done, because I don't think that will bring people into the park like they are hoping. But last I heard, they are still deciding what could go there.
Last I heard, an Australia section was gaining ground on BK. It wouldn't be as hard to create as the Asia and Africa sections since kangaroos and wallabies are considered the vermin of Australia. Koalas may be another story, but throw in a few platypuses and a couple other weird-looking things and you got a new animal section!!! Knowing Disney, when they have a hit on their hands, they like to put the thing EVERYWHERE. They are desperate to clone Soarin' Over California somewhere in AK and current plans have another coaster (a real one!) going in the park in 2004. A thrill ride, a family ride and an animal trail seems like the easiest way for Disney to expand right now.
The coaster could go in as part of BK, though. Last I heard about BK was that the coaster and land would go in first, with a major dark ride to follow a couple years later. How Disney is that plan??? Disney is SO jealous of Spider-man over at IOA that they are desperate to do something similar in WDW. If they can figure out something, then I would think BK would be the winner in the New Land Race.
If I had to place a bet right now, I would actually go with the Australia section. Soarin' Over California is one of the few highlights of DCA and copying it would be far less expensive than creating something new. Some say a clone could go into Africa also, near the Yawnservation Station (Rafiki's Something or Other now) but being able to advertise A WHOLE NEW LAND seems smarter. One more reason I think Australia has a chance has to do with Disney math:
1 Coaster + 1 Clone + 1 Animal Trail + Trees for Theming = Pretty Cheap!
1 Coaster + 1 New High-Tech Ride + New Fanciful Theming = Not Cheap At ALL!!!!!!!