- Sometimes websites require flash to navigate them.
- Sometimes you actually do want to see what's behind the flash (Google Video. Homestar Runner).
#2, of course, can't be helped. But #1 "should be" easily fixable: When asked to render a Flash object, have the browser instead stick in an iframe (or scrolling div, whatevs) that contains all of the links that the flash would (eventually, ugh, after waiting for all the text to scroll in) show. You could even have a "replace this with the real flash" link, making this a superset of the awesome flashblock's functionality.
I looked into this: I think most of the SWF parsing could be handled by gnash or swfdec, but it's unclear to me whether these support the most recent flash versions. But if they do, then most of the hard work is doing the browser integration. You could do it with Greasemonkey but then you still get the annoying double-load of the page 'cause Greasemonkey gets at it too late, so it'd probably be better(?) to register yourself as a mime handler for flash, and then reregister the actual flash player under a new mime type.
Me, I've got plenty of other projects. Mozilla hackers! I invoke the lazyweb! (I'm looking at nikolasco as my best bet. Or maybe mart.)