I see everybody complaining about fast release process of Firefox.
It would be a pain to have it integrated.
If addons developers can't follow the speed, I will be very upset with the lack of support.
For corporate deployments and for users that cannot use Firefox with specific addons, there has to be a stable branch that includes security updates.
As long as they keep the 3.6 branch alive, I've no problem.
Else, it would be a real PITA.