Flash is generally always "playing", whether you see pictures moving around or not. I don't generally see fit to blame the browser for what I see as a Flash problem, be it poorly written applets or an unoptimized/buggy/whatever Flash plugin.
Was Flash performance really better in Opera? As I've said before, I didn't use Opera for long, but I seem to recall Flash not working nearly as well as it does in microB.
User experience and usability are very important to me, I just think some have unreasonable expectations.
It could certainly be faster, and I expect it to get faster.