I worry that this is yet another reduction in degrees of user's freedom to tweak, tune and adjust FF. Back when FF killed all XUL extensions, it lost one of its

I worry that this is yet another reduction in degrees of user's freedom to tweak, tune and adjust FF. Back when FF killed all XUL extensions, it lost one of its most uniquely valuable propositions. Yes, the change was required to make the browser more secure but at the time we were assured that new APIs supporting the lost functionality would come. It's been nearly three years since the change was announced and the functionality of several of the most popular extensions (like Tab Mix Plus) are still impossible to implement in Firefox. I strongly support the mission of the open web but as a heavy FF user I'm not happy with the prevailing attitude at Mozilla that seems either against user customization.