Nothing about this change applies a change in quality. It's the opinion of a few vocal people that this is bad, nothing more.

I don't like this change but haven't publicly remarked about it until now. What about the vast majority of people who don't browse hn or haven't been provoked into making their opinions heard? Dismissing opinions you don't agree with as vocal minority won't help you and certainly won't help Mozilla.

Mozilla like other companies providing user-centric products must conduct focus groups to see what works and what doesn't. Relying on designers' ideas without proper validation is a recipe for disaster.