Oh joy!The WS-MetadaExchange specification has been updated. You can find the new spec here: http://specs.xmlsoap.org/ws/2004/09/mex/WS-MetadataExchange.pdf.
In general, the idea of representing everything as a resource holds tremendous potential for managing the service; while the spec does not mandate it (everything revolves around Get), you may think of using WS-Transfer's Put for actually pushing info to the services under your governance.
Hopefully in the next days I'll find more time to get an deeper look to it. Check it out :)