Definitely wander over to the DVC boards and also check out the DVC page at allears. In my opinion, if your travel habits are just as you say, I would say skip it. Although you can use your points at many II timeshares around the world, you may be better off buying into another "brand" of time share if you only really visit DLR of all the Disney destinations because your home resort would be at WDW. We have been members for only a year now, but have used our points at GCH and SSR at WDW. We plan on visiting WDW at least once a year and DLR probably about once every two years. Look into it and decide for yourself. You can always call DVC, too. They are VERY low pressure sales...explain your travel habits and I think they'll be very upfront with you.
My other suggestion, go visit WDW!!! Get the best of both worlds!