This post would have been fine if you could have just left the whiny parts out of it.
I'm extremely surprised and disappointed this is the route they went. I agree that mana regen is out of control, but this is a sad reaction.
As has been said above, this penalizes smart play and doesn't offer any compensatory rewards.
A much cleaner way would have been to remove or drastically scale back the xx% mana regen inside FSR talents. From a Druid/Priest perspective, this would even more significantly reward those two classes when they planned ahead and coordinated through smart HoT rotations or stop-casting respectively. It would also encourage smart planning in gear (am I going to want to stack mp5 this bursty fight because I need every GCD, or can I use my Spirit gear for a more endurance-based encounter where I can slip outside FSR?)
Now rather than smart playing and smart gearing, there's no reason not to just stack MP5 and/or cast without any overall strategy.
Pallies are getting their own nerf, and Shaman are already considered the only healer that is currently where they should be at regarding mana use according to Bliz, so either of the two options (mine or theirs) would have solved the issue.
Too bad. This really ruins a major part of the fun of Druid healing for me