I'm not a fan of the trend toward monochromatic, low-contrast desktops. Colour iconography seems to be frowned upon, whereas it's a definite aid to speed of comprehension. The settings list in particular is just a sea of text with small icons that are only minimally useful. Microsoft went this way with its Metro design language but has come to its senses in more recent years and both Windows and Visual Studio are more colourful now.

I'd recommend a tweak to the amount of whitespace, too. I'd prefer smaller dialogs or a larger default font (and maybe a wider one, too) to balance out the vast areas of blank space.