Even according to my position that the glibc has 0 responsability in the way Flash misbehaves, I agree with you that the end user should, when possible, not be punished. I think this is clearly the job of distributions, that can identify, given their target and if they have the occasion and resources, which interaction exposing a bug in some piece of software is acceptable, and which is not. Maybe some distributions will indeed make the choice of temporarily reverting this optimisation, but I hope Adobe will simply have enough time to fix their stuff before lot of distro are released, and if the timing is OK maybe the distributions could pressure Adobe by sending them a clear message that they will ship with the best technology anyway, so that it's up to Adobe to cleanup their mess if they want that flash continue working correctly under distro X. If the timing is bad, I would clearly prefer an automatised LD_PRELOAD style work around (if done transparently for the end user) to a whole system disabling of an optimisation.
But I would not even be angry against a distribution that makes the choice to not care at all about Flash. I perfectly understand that some can absolutely not care about Flash, in which case an angry user should just do a workaround himself or switch to an other distro, if he indeed is not in the target of the one he used.