I really think if you are flying halfway across the globe to another country, experiencing that country's culture / visiting their famous sights should be your focus, the Disney park or cruise is really just the 'icing on the cake' 'tick off bucket list' thing that can be the impetus for the trip but not the only purpose.
Most people's holiday time is finite, so in this case, I actually think 3-4 days at sea cruise length on th
Disney Adventure is perfect, it's enough to scratch the Disney itch, there is so much to do on board already to fill those sea days, and if you fly so far to get to Asia, you would want to spend more time exploring rest of Asia rather than being on a
Disney cruise the whole time.