Flash block -> Plug-in management
Rather than providing functionality specific to flash, it would be great if it were possible to set permissions on plug-ins in general or on a per plug-in basis, i.e., have "always run", "notify", "never run" options for plug-ins, with notify behaving much like the current flash block extension, perhaps with a louder page load notification than flash block uses. The notification could also provide the option to run all plug-ins on the page.
Never run would be useful for users that wanted to a have a plugin available/installed, but only use it rarely and didn't want to bother with it most of the time. I guess it could be like flash block, but without an onload notification. It might be better called "silent".
The overall idea is that flash-block is can be argued to be overly specific, but better/increased plug-in management is very useful.