The day Bitcointalk allows animated signatures, is the day I'm going to enable "Don't show users' signatures".
Once in a while I see "the internet" without Adblock Plus and without "image.animation_mode once", and I hate it with a passion. I'm okay with some ads and some animations, but it quickly gets overused.
Yes, you have said it all, I fully share this point of view.
Moreover, one might ask what the real added value of animated signatures would be? I'm not sure if it's necessary to overload the forum pages with useless info/designs, as the hero/legendary distinction is already made through the forum users's profiles and is clearly visible in every message posted.