Rebranding and image polishing are undertaken only when a company knows that things aren't going too well for them. Many Firefox users would probably agree with that, at least the technical users know it all too clearly.
However, the problems are not caused by the brand being unsavoury or the image tarnished. The brand and image are fine. Where problems have appeared it is because Mozilla developers have been forcing unwanted change on their users, forcing them continually to find remedial fixes to preserve friendly and productive old functionality. Browsers are not kettles, people don't want a completely different look each year.
The fact that Mozilla is now undertaking brand and image refurbishment clearly indicates the nature of the problem. The immense and unbridled ego of Firefox developers has put them in complete denial that Mozilla's problems are caused by them and them alone, and that has left their management with only one alternative, to play with branding and image.
It will achieve nothing of substance.