That's wonderful, and if you make it a configurable rule (I'd have mine set at 10% if I could, I want uber fast regen to counter the fact that monks are all screwed up on the emu and way way way overpowered, so a soling monk, FD, I want them to get hammered by mob regen), it would be perfect.
Also, KLS, just throwing this out there, you may want to make sure the doesn't affect pets too. Dunno why, but something tells me that it could.