Each skin should add its name (or ID or whatever) as a class in <body>. The reason I request this is that it would enable gadgets to change the CSS of a page in different ways depending on what skin is used.
For an example, turn on the "Dynamic menus" gadget on Meta; it is only intended for Modern, and will look awful in other skins like Monobook or Standard. With a CSS identifier for each skin, it could be adapted (or disabled) for other skins than Modern, and avoid making a mess.
Version: unspecified
Severity: enhancement