I'm an Android user (HTC Desire), and I have no problems with Flash content. My phone doesn't struggle, or die. Battery life seems unaffected for my usage pattern. Mostly it is used for embedded Youtube/Vimeo/Facebook etc videos in news articles and blog posts. I have freedom. I quite like the iPhone 4 as well, but it does not give me the same freedom and choice as Android. Not a train smash if I didn't have flash, but having the freedom to choose is way cooler.
As per seeing the web with adverts, I prefer it this way - don't really mind. We've really moved on from the ugly flashing adverts, scareware, trickware, malware, popups, etc of the late 90's and early 00's. I couldn't care less if the adverts were flash-based or PNG or GIF. I often do click on adverts if they interest me, and have found some really good companies, online stores, and specials. Also found a crap-load of other nonsense, but those are dealt with swiftly, painlessly. I tried using ad-blockers and flash-blockers, but the whole web experience just seemed emptier.
The internet without Flash or adverts, is like driving through JHB with no taxis. It just wouldn't be the same, less colourful, more monotonous, arguably more peaceful.
In any case, point is, you should be given the freedom choose.
I think Arstechnica did an investigation where they compared a MacBook Air's battery life before installing Flash and afterwards. It decreased battery life by 3 hours.
And no, if you give people the choice, they will will make the wrong choice, and enable flash (Without having a good reason) and blame Apple for the poor user experience.
If a person really wants flash, they are free to use any other phone. But most clearly aren't that committed to Flash