My opinion... No! Of course flash still works for me so my opinion is maybe a little biased... But I think what you would lose in everything else would not make up for the slight gain of flash.
You can download flash. Some people (my self included) have downloaded flash and had it work well. Others have had terrible luck with it. Download it and see it won't hurt your device.
An iphone doesn't have flash either.
The switch is up to you we're all going to be biased around here
Depends on what you want mate, I wasn't fully satisfied with eithe OS...now I carry an iPad 3 and a MAXX and love it. Do you want a big phone? Do you want a little phone? 4g? Battery? Smoother but less customization or more customization and a slightly laggy experience? Are you an apple fan on your other hardware? Are you an android fan on other hardware?
Flash works great for me. I have adobe flash installed and adobe air installed. I also use vlc media player instead of the standard player that comes with ics. I have no problems with south park studios and all other websites that use flash.