Shoutbox

Yup. On each skin it says the compatibility. All the skins you listed say: "This skin works with Messenger versions 8.5".

It explains why, here: http://www.msgpluslive.net/skins/help/#compatibility

So, only skins that say they're compatible with 9.0 (2009) will work.

Personally I don't see any problems with the new Messenger. It looks fine, you just need to get used to it.