Earlier quoted context omitted.
XUL is insecure legacy tech. There isn't a coherent argument otherwise: XUL is insecure in that it gives addons all the power of the browser, and XUL is legacy, unspecified, single-implementation-wedded XML stuff from the '90s whose functionality has been entirely superseded by HTML at this point. The idea that nothing can be insecure and legacy unless the new alternatives support absolutely everything the old techno…
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…
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.