With the most recent firefox, I've noticed flash causes crashes 1 crash a day. quite honestly, until adobe overhauls flash and makes it secure, fast and not a memory hog, flash on smart phones is a horrible idea.
In my previous life, I wrote an SWF decoder. Well, let me say that I now have a HUGE respect for Adobe. Flash has the best model for vector graphics I've seen so far (it uses a list of linked regions and not just a list triangles), and its renderer is pretty good.
There's no way you can make something with all the capabilities of Flash (smooth animation, antialiasing, compositing, good font rendering) much faster than Adobe. Even hardware acceleration won't help you much - it's _still_ not good enough for fine antialiased drawing.
Don't believe me? Try to load a 'resource hog' Flash game ( http://www.kongregate.com/games/IriySoft/cursed-treasure-dont-touch-my-gems - for example), right click on it, and set quality to 'low'. Notice how much less CPU it now uses.