What's there really to improve? I don't think the experience with Firefox is fundamentally different, nor could it be made fundamentally better. It's a browser. People don't care about browsers, they care about websites. Even if Firefox were to implement some fancy feature, websites aren't going to adopt it until Chrome has it too.

Sure, you could argue that Firefox doesn't track you like Chrome does. That's basically their whole marketing message. People who care about this already use Firefox, the rest just doesn't care.