Why don't you just disable blocklist in about:config?
I have used the Proxomitron since 2002. It gives me a toggle switch for Flash, Java, etc. I love that because the last thing I want is Flash automatically playing some dumb video when I go to a site. So, I don't see the objection to "click to play". As I understand it, there is no "blocking". Mozilla is doing the same thing Proxo has always done....Mozilla is just very late to the party.
I don't use flash on Fx anymore though at all because of the two crap services connected to it that Mozilla has so badly designed that they have to run all the time for no reason.
My current concern is HTML5. Why is Mozilla not also making that click to play? They should.--
When governments fear people, there is liberty. When the people fear the government, there is tyranny. Thomas Jefferson