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" and behave exactly like flash block, with the option to run the plug-in by clicking on the in page indicator, but no notification.
The overall idea is that flash-block is can be argued to be overly specific, but better/increased plug-in management is very useful.