Sybixsus: Why shouldn't they drop it? Actual program may be executed within a "sandbox" anyway for stability and compatiblity reason (as they rely on GDI which is replaced with WGF) and there is no reason the sandbox shouldn't emulate a registry for this old apps.
I said dropping all support for it would be insane, not stopping using it for the future. Fish's implication was that using the registry was a problem because Longhorn was just going to drop it completely. Longhorn will probably drop a lot of things, but I doubt to the point where programs which use them will have problems running.