"Flash does have its purposes and will have its purposes, the same as [Microsoft's] Silverlight and others, especially for dynamic content.
Guess what? That's exactly what Flash was made for and this is exactly the area where EVERYTHING else completely sucks, including HTML5 (which as of today NO browser actually supports), Ajax, Silverlight, Java and countless other failed approaches.
You want to implement something that's platform and browser independent and that actually works? Flash is the ONLY option. End of discussion.