Yes, the graphism of the addin is going to create by another company. If I use MCML, I will do also the graphism. With Xaml, the graphist can use the Expressions' tools.
Also, I don't like to learn again another language (C#, java, xaml, php, css, html, c++,xml,rdf,sql,etc...).
But it's strange Microsoft said the XAML is the future on everything but not in Windows Media Center... Same LiveStation is with Silverlight and it's probably the future of Media Center or an future part of Media Center 4.0. What do you think about LiveStation and Media Center ?