This is much more a "defacto" design than the panels you referred to (bitrix, joomla, vivvo). You get used to certain conventions and they feel like "defacto" approaches, until something much more intuitive and natural comes out. It isn't long ago when people were bashing "windows" as a gimmick, insisting that command prompt and NC-like skins is the proper way to interact with a computer. "Drag'n'drop? WTF!? Give me F5 and two consoles".

We're entering see more the age when software is changing into something that looks a lot less as software and a lot more as a set of toys from your childhood - simple, friendly and intuitive. Intuitive not only for those who can name 3-4 CMSs in one breath, but for any mom and pop that would care to create a site to extend their hobby.