Because I had played it awhile ago (in advance of advertising it - indeed, as a condition) I've had a chance to talk with people at conventions and so forth about my experience with D&D4. Or 4E, or whatever the accepted nomenclature is. As I have said, the alterations are radical. I mean radical in the sense that evokes a skateboard launching from the lip of a pool, but the changes (and the deprecation of your previous supplements) are a serious matter I am not deaf to.
This is one of the things I love most, perhaps, about the sacred table. There is never any point at which your old books, dice, and mechanical pencils may be "revoked" by Wizards of the Coast, or any other kind of wizard. The same can't be said for gaming of the electronic sort, particularly on consoles, where the back-end services that sustain a game are not guaranteed - particularly as gaming has become a "service." Impermanence - for example, constraining access to a game you have purchased, with a recurring subscription - is core to certain segments of the business.
My Dark Sun and Planescape supplements, bought by the sweat of a young man's brow toiling in the dish pit, still "work." It's one of the reasons I'm very comfortable advertising a new version. It's not a Madden scenario, where if you opt out for a year your experience grows increasingly desynchronized from reality. Here, you're making reality, at least, making a reality - that's what the whole Goddamned game is about. There's a fairly strong disincentive to buy into a different system, which places a grim onus on anyone who wants to sell you a new one.
(CW)TB