I don't know why you mentioned Linux when it has a ton of window managers which provide real alternatives to any specific UI design. Window Maker looks different from fvwm95 looks different from IceWM looks different from <insert tiling WM here> looks different from TWM... and all of those window managers are usable, to the extent applications don't care what they're running in and the OS itself doesn't care about window managers at all.

So you can have the UI of your dreams, or at least a UI which is honestly different from what you're railing against, if you just open your eyes a little and see beyond the defaults.