It's probably not a bad thing.
They do have the data to back up their move.
(Sending in those crash reports does help.)
They know well what plugins are vulnerable or that do cause crashes.
"Plugins" are the new game & everyone & their sister wants in on it.
All kinds of crapware now end up installing plugins, often unbeknownst to the user.
Take a look at your plugins right now.
(about:plugins & about:addons)
Just what do you have? Anything related to .NET? Windows Activation Technologies?
Just what in the world would anyone need anything like that for?
(Mine says Flash, & the rarely used anymore, WMP plugin.)
Ages ago, I may have used Quicktime. Possibly Real. Bugs, crashes, in those days had forced me to give them up. These days, it is (for me at least) rare to even find those formats & if I happen to, I can download the media & play it in my media player. (That likely is not a viable option for all.)
Would assume even if there is a blanket OFF, there will still be afforded (about:config) Preference methods to enable particular plugins.
During this change we will monitor the results and feedback of the new settings and UI to ensure were providing a quality experience and delivering the many benefits of Click to Play to Firefox users.
And I'm sure they're going to hear a lot of flack about this, & are prepared for that too, & that will affect how they go forward.