personally, i knew things were headed in the wrong direction when they added that big orange button in the top left corner. i guess that was version 4. i felt like it was the beginning of the end.
Around that time, they also added that Keyhole shaped back and forward buttons that looks off on all platforms. That's one of the first instance where I felt they prioritized what they want - a brand identity, over what the users want - a consistent user interface.
https://web.archive.org/web/20120725235602/https://blog.mozi...