Earlier quoted context omitted.
I seriously believe that the last time any real thought went into usability in UI was with Windows 95 - and even that wasn't free from form-over-function issues. In Windows 3.0 it was meant that only elements you could interact with the mouse would have a beveled 3D appearance, so people would know just by looking at a screen what they would be able to interact with. However it wasn't fully followed - checkboxes, rad…
What are your thoughts on KDE in regards to an accessible Linux distro?
I haven't used KDE much but from my little use i found it better than GNOME - mainly thanks to Qt - but still leans a bit too much into the flat trend (especially some newer things that use QML instead of Qt Widgets). Still, if i absolutely had to choose between the KDE and GNOME i'd choose KDE. Fortunately there are more choices and if i had to go with a desktop environment that currently exists (as opposed to my fantasy one :-P) i'd go with XFCE.
Though in practice i use Window Maker, but that is mainly out of habit as it doesn't exactly match what i'm talking about. But I do use Thunar as a file manager and Mousepad as my notepad-like text editor.