Supposedly, Windows 8 will come in several flavors, with one or more intended for the tablets, and which would be very conservative as far as resource requirements and resource consumption (battery life).
Thus, it wouldn’t be a power hungry version of Windows 8, but would still offer a better and more powerful experience than the tablets of today.
You cannot support Adobe Flash and have reasonable resource consumption - they are mutually exclusive.
There are 2 primary ways to display movies. Hardware acceleration uses specific chips that work with very few codecs - and ALL this chip is able to do - is play that codec. This chip's ONLY function in life, is to play a codec to display a movie. This uses very little power.
The other way is 'Software Emulation' where you use the processing power of the processor to play many different codecs. Now you can 'play' almost every codec known to man - but you must now compute the value of every pixel - and the result is that you chew up power. On a mobile device - this is murder.
So, a iPad gets 10-12 hrs on a charge playing H.264/.mp4 file format movies; or it 'could' run Flash and give you 2-2.5 hours of battery life. That's one of many reasonsy why Apple iPad tablets do not run Flash. And one of many reasons that the Tablets that do run Flash - are not selling well.