The icons need color for easy differentiation. These crisp monochrome icons are nice in theory, but when you're quickly scanning for an icon it all goes to mush in your vision.
They are not nice in vision theory at least. To make them as differentiable as you could, they should all have different texture, orientations and colours.
This icon style is called Sifr. There are five other styles available in the View section of the Options dialog, which seems like at least three too many. I'm trying Oxygen for now.
