This is fairly old post but I'm bored and ended up here. =p
(Really not sure how I ended up here, just kinda started writing. <.< )
I can say I would be "severely displeased" to have a +Version of a game released on a random console as I have regretted front line purchases of KH years down the road every time and missed all that content.
That said they don't really expect to get anything here right? In my opinion Game content is developer property. It's like buying a really interactive painting from a giant multi-faceted Dev/Art-Hydra. You are free to hang, hide, sell, burn, eat the finished product, but it will always be the creator's work. If they painter comes into a random assortment of homes and puts a well textured mustache on the finished product for free because he felt the art needed something more. Is it wrong if he leaves half the people out?
There, I have now made this question significantly sillier.
Long story less psychotically put; I know why they are mad, but the Devs can add what they want when they want, at least they aren't RETROACTIVELY REMOVING CONTENT from the previous version.
(No one would ever remove content from a finished product though, would they Sony?)