Certainly some will go for shorter times but even for west coast, I think 5 days will be the minority. From the rest of the country, a full week is the minimum MOST people will go and many won't go unless they can go more than a week and often around 2 weeks or more. Don't get your hopes up about Asia. I don't think they are nearly as active in HI as they were a number of years ago and to most of them, it's just a nice timeshare of which they are a number of others choices that are more aggressive and likely better choices for non WDW options.
I don't "have my hopes up" though - I was just wondering if indeed they are opening an office there. Also, I think the combo of Disney and Hawaii will increase the draw from Asia and likely from the US, too. I suspect that won't apply to seasoned timeshare owners such as yourself, but many people are only willing to consider a timeshare because it is Disney - there is truly a certain amount of brand loyalty there.
Also don't many people split trips among multiple HI islands? The trip may be 7 days or more while the stay at the DVC is 5 days or less. I would imagine this will figure in, as well as people buying with the intent of banking and borrowing for other-than-annual trips.