The thing is that you were complaining about SeaMonkey due to how it looks, even though the way it looks is generally associated with an era of software design which expected much higher degree of reliability and user control than is common for "modern" software.

I don't think that's a purely contingent association, either: with software, how the UI looks and how the functionality works are deeply intertwined, and I think there may be a more direct correlation between "modern" software being unreliable, unconfigurable, and insecure, and it having haphazard UI designs that lack underlying organizing principles or adherence to well-established conventions.

So your original complaint seems to imply almost the opposite of what you are saying here -- that superficial aesthetics are more important to you, even to the point where you'd accept poor functionality and user-hostile anti-patterns as a viable tradeoff.