Dean-
I am not sure if I am misunderstanding you or not- but, from what I was told at least- your statement that "many weeks given up by those enrolled will never make it to II but will potentially be available to other enrolled and points owners independent of II" may not be right, unless you you mean enrolled owners giving up their weeks for points that year.
The way it was portrayed to me, at least, is that week owners would be trading for week deposits, and point owners for enrolled week owners who converted to points for the year deposits, point owner inventory, Marriott unsold inventory, and Marriott inventory from people trading in for reward points. Of course, Marriott reserves the right to dip into the week deposit pool, but supposedly II will be requiring a comparable trade, like they do from everyone else.
So, the way I see it, you might see a lot of high end newer resort availability from Marriott inventory as trades for higher demand sold out properties.
An interesting twist to the issue of relatively undervalued weeks- those properties which command a high rental rate but whose point allotments were really out of whack with the rental market will be perceived as better point values. For example, Aruba weeks which rent for 6k by Marriott were awarded less points than weeks that rent for 3K. As a point user- which would you think was a better value for use of your points- somewhere which Marriott charges 3K for the week or where they charge 6K? I expect demand for the Caribbean properties to be high and where there is little Marriott inventory they will need the weeks owners' deposits to fill the requests. I expect that most owners of the properties where the point allocations aren't commensurate with perceived value will find better value in trading in weeks. I know I was told by several people that, basically, there were some properties where trading in weeks will be better for the owner because of the point allocations. So, it may be that high value properties that suffered in the point allocations will enjoy increased demand in II, because Marriott will need those weeks to fulfill requests.