The 2012 numbers are said to be less than encouraging and it's clearly not the economy as Disneyland's and Uni's numbers remain up.
It's hard to figure out where the ceiling is for WDW given that the resort pulls in guests from all over the globe. But certainly, they'd like modest growth given that the U.S. population is growing, and given that countries such as China are rapidly growing a middle class, the market is growing.
Potterland has brought in more guests to Uni, and you'd think that this would have increased, modestly, guest levels at WDW. If a family comes to see Potterland, you'd think they'd also figure out how to work in a day at WDW. Flat attendance numbers are bad news, it means that even with "help" from Potterland, i.e. millions more tourists are visiting Orlando, the resort has sort of stagnated.
I think WDW has two big problems:
1. Poor upkeep. Splash falling apart, and the condition of the parks in general is not great.
2. Not enough attractions. They took out Snow White, yes, 7DMT is coming, and Mermaid is there now, but the wait times are ridiculous and growth in attractions hasn't kept up with increasing numbers of guests.
What has happened is that the parks are crowded, not kept up well, and it has knee capped growth so that it has stagnated, and probably will dip a bit. FLE will bring in some gawkers, but while Mermaid's outside looks good, the guts of the ride are the same as the one in DCA, and I just don't see it being a big draw years for now. I think 7DMT might draw some attention, but we'll have to see.