Why push out something half baked? You are essentially stabbing your users in the back, some of us depend on those add-ons to get through the working day. To come into the office one day and to find your work environment irreversibly borked is not something that I find it all that easy to forgive. You have a very large responsibility to your users to not mess up their workflows. Better to keep your update in-house until you are done than to push something half baked and not backwards compatible.

'a bit bumpy' doesn't begin to describe it, until this day there are many ways in which the current iteration of FireFox is behind where 56 was.