I think people are overlooking some key statistics in the design of this cruise ship..
The ship is just a tad smaller than Royal's Oasis-class ships (Which my family LOVES by the way, also Royal has 5 of these ships and has no issues filling them, I think Disney can handle 1 oasis-sized ship)
The Largest of these, the Wonder of the Seas has 2874 staterooms, but a "Capacity" of 6,600...how do they calculate that? Simple. They have 18 life boats that can hold 370 people each. (in case you are wondering, ships never have enough life boat space for all passengers and crew, they have inflatable life rafts to accommodate the difference in crew)
The Global Dream, in comparison, has 2350-2500 cabins (depending on which press release you read), and rather larger cabins than industry standard. Most cruise ship cabins are 14-17 sq m, Disney tends to be larger in the 15-18 sq m, the Global Dream has 20 sq m rooms.
So its basically an Oasis-sized Ship, with about double the number of staterooms of a Dream/Wish sized ship, but with cabins slightly larger than those in the Disney Magic/Wonder.
How do they claim 9,000 capacity? Well renderings show 20 life boats on the Global Dream. Its not to hard to believe they have slightly larger lifeboats that can hold 450 people each. But this also means to hit 9,000 people, almost every room on the ship would have to be filled with 4 people.
Asian families tend to travel as generational groups (kids, parents, grandparents), so if this is targeted at the Asian Market I can totally see 4-5 people per room, or up to 10 people in 2 adjoining rooms.
I can also easily see Disney setting the capacity as something closer to 6,000 with the usual 2-3 people per room occupancy they have on existing ships, that is IF they were thinking of bringing this to a US or European market. If they plan to keep it in Asia, then this may be exactly what they are lookign for.
Would this impact pricing on existing Disney cruises? I doubt it. The Asian cruise market is very different from the US one. Different economics & demographics. It would be comparing an apple to an orange.
I personally would love US-based, Oasis size and style ship, themed as Disney. I always thought Disney could have done amazing things with a split hull design, like Royals Promenade but Main-street themed! Sadly, I truly do believe if DCL buys this it is to keep it in Asia, but I see a lot of potential here.