That makes sense--it would be as though Poly/their system was another outside exchange program; in other words there would still have to be some benefit to the overarching/multisite exchange (whether it be a fee or something else).
That said I really don't see WHY DVC would do that. Their model is successful as is, and they pretty much name their price and clearly haven't found the ceiling yet. A huge selling point is the versatility of the points, even at those 'prime' locations--so I suppose if I was an exec I'd be of the mindset that if it isn't broken I'm not going to bend over backwards to 'fix' it... when the fix may create a host of unknown issues and certainly legal challenges by their many affluent and educated current owners. As it stands, every DVC resort strengthens the brand by offering a different vacation experience.
So although they 'could' do a lot of things, the cost/benefit of doing most or many of those things just doesn't pan out IMO. I think they are going to have TONS of current owners that snap up Poly points, and tons of people that are lying in wait to buy DVC at the Poly--and again, they can kind of name their price here, so it's not as though they need to create a new, suspect tiered system to sell the points especially when they can save A LOT of legal $s by using a version of the structure they already have.
As a new Poly owner, would you like having to pay a $50 exchange fee to book a non-home resort, or would that feel insulting after you pay a gazillion for your points and MFs? Or even say they build in those costs as part of a VIP membership or part of your MFs... as these boards will prove, people get pretty penny-conscious with maintenance fees and if members feel that they are the only ones paying a premium for something they don't use as much as others (i.e. extra towels, shampoo) how do you think a Poly owner is going to feel about paying a premium in the MFs for a service that other DVC'ers get to use for free (the exchange of resorts).
As an existing member, would you like having to use a different booking structure and learn a different system to book for your Poly points? Remember, existing members are a HUGE part of their target market. We're proven customers and they know we get addonitis

They also get lots of sales by word of mouth, and if current members feel screwed by the new property, they are likely to badmouth DVC, sell off in large numbers (sinking new sales by flooding the market) and create a publicity deficit at a time that DVC will need brand strength.
Feel free to disagree with me, but I think most of the rumors come from cast/crew's perhaps accurate assessments that it will be PRACTICALLY difficult to trade in to stay at the poly bungalows or get space if it is your non home resort. But that was also said about VGF, one of our home resorts, and it seems like non-VGF owners have definitely able to trade in so far.