As Cropman has pointed out above, "this thing has more secrecy than the White House"--which means the rest of us are forced to stumble around in speculation and confusion until Hyatt Pure Points Program is formally announced. That said, my understanding is different: PPP inventory will be separate and distinct from the Legacy program. PPP owners will not be able to reserve within the legacy program, and vice versa, unless legacy owners decide to purchase separately into the PPP. There have been comments here about PPP and Hyatt exercising ROFR to buy attractive high demand inventory and place it into the PPP, effectively moving that inventory from the legacy program into the PPP. That is being done and has been underway for some time.
Does this potentially limit the attractiveness of the legacy program in terms of owners being able to trade within the legacy system using their points? Potentially, yes--especially if Hyatt gets much more aggressive in buying up those prime weeks and moving them to PPP. But as Kal has pointed out, Hyatt does not appear to be on a mad buying spree, and so I remain optimistic that the legacy owners will continue to have ample opportunities to trade within the HRC system for years to come.
That said, my advice to HRC owners is to avoid "owner's updates" like the plague. The sales weasels will be conjuring up scare tactics like we haven't seen before, with doomsday stories of the demise of HRC and all of the attractions of Hyatt Pure Points, allowing a one-time conversion special of only $xx,xxx in order to make the switch before the HRC program collapses. Just ignore them, enjoy your HRC vacations, and pay attention to the TUG boards to get more realistic information.