The fact that Adobe acquired Macromedia was quite unfortunate for the web. Had Google acquired it, they would have probably opensourced the player code, and maybe contributed the AS3 rendering engine into WebKit as an alternative to javaScript, making Flash native for WebKit browsers. Maybe it's not too late for this step even now.
Tamarin ain't bad, but for me the main advantage of Flash right now is the relatively fast, browser-independent and (unfortunately) closed-source rendering engine.