I'm using opera as my main browser, and I have to say that flash is often broken.
But flash is mostly animated ads, mini-games or video players, and occasionally navigation menus.
I don't want to see ads while surfing, especially those animated or blinking or talking or making sound.
Playing flash games and watching streaming videos has made me spend time I could have used to do something useful.
When I run into a website with a flash only nav menu, well I just hit the back button, if they had interesting content to share it's too bad they chose to share it with only flash user.
So I'd say I'm quite happy that Opera / Linux isn't fully compatible with flash yet, it has actually improved my usage of the web and what I do with my time.
BTW the "click to activate" problem is related to how people invoke flash objects in their code. When used gracefully (as with ufo for example http://www.bobbyvandersluis.com/ufo/ ) this doesn't happen.