Now a days everyone is going to the basic. Microsoft has already moved to the basic when the Window 8 was introduced. It has totally flat view.
Similarly Apple is trying to achieve the basic flat design in iOS. It begins since iOS v.7, by removing glossy effects over the application icons.
How WordPress would stay behind? The new version 3.8 of WordPress has introduced all basic flat UI. No gradients, No glossiness, No clearly visible heavy rounded corners, Dark shades of colors, CSS arrows, Text icons instead image icons. A simple flat background color makes it look really eye-catchy!
Even the buttons, menus, sub-menus, tabs, section headings are also made flat.