Is there a list somewhere of which extensions have been deemed "important"?
As far as I'm concerned, every single Firefox extension I currently use is important, regardless of what Mozilla thinks of their importance.
I also have several extensions that I wrote myself for my own personal use. I'm not looking forward to having to modify them, assuming they'll even work with the new model.
This is a good example of the Firefox brand being tarnished.
The name "Firefox" used to make me think of empowerment, and being able to get so much more out of the web browser and the web experience.
Now when I think of "Firefox" it makes me think of uncertainty, of broken extensions, of my time being wasted updating my own extensions, and of enduring all of this for little to no benefit to me.
There's a tradeoff between keeping legacy code working and deprecating old APIs that are holding the platform back. Keeping all extensions working without changes is essentially incompatible with the migration to a sandboxed, multiprocess browser. Keeping XUL is incompatible with any future migration to a next-generation layout engine. XUL also holds back Gecko development because Gecko essentially has to support two different rendering modes; time spent keeping XUL working is time not spent improving security and performance of the Web stack.
Even if you don't want those architectural improvements, a lot of people do, and I find it hard to blame Firefox for doing what's best for the needs of the majority of its users.
Don't get me wrong, I'm not against Firefox improving and evolving.
And I really don't care if Firefox is or isn't using XUL. As a user, that's quite irrelevant to me.
However, as a user of Firefox, I am weary about being put in a position where the extensions I depend on no longer work, and either I don't have any recourse (if what the extensions do is no longer permitted or possible) or the recourse involves a large expenditure of effort on my part (rewriting my own private extensions).
The friction of using Firefox has been steadily increasing over time for me.
At this point, it's only the Firefox-specific extensions I use that keep me from switching to an alternative browser.
I know I'm not alone.
Many in the Firefox community already went through the broken extension experience back around Firefox 5 and we are not eager to go through that again.
If Firefox users do experience problems with these upcoming extension changes, then I fear it will be the last straw for many of us.
And if there's one thing that Firefox and Mozilla really can't afford right now it's to lose more users. There are very few of us, relatively speaking, as it is.
I'm less worried about the architectural improvements than I am Mozilla's blasé attitude toward making things work - history shows us that MO is to break it and fix things later, rather than releasing something that'll be mostly feature complete on day one.
As far as I'm concerned, every single Firefox extension I currently use is important, regardless of what Mozilla thinks of their importance.
I also have several extensions that I wrote myself for my own personal use. I'm not looking forward to having to modify them, assuming they'll even work with the new model.
This is a good example of the Firefox brand being tarnished.
The name "Firefox" used to make me think of empowerment, and being able to get so much more out of the web browser and the web experience.
Now when I think of "Firefox" it makes me think of uncertainty, of broken extensions, of my time being wasted updating my own extensions, and of enduring all of this for little to no benefit to me.