I think it has a lot of potential, especially if there's a hidden control over IP protocol (Yamaha is good at creating really robust control protocols (like for their RS232 controllable equipment) and only releasing them to installers - until it's leaked out to the general public...). Just of that receiver combined with their music cast system and clients all around the house - you;d have a very robust "all hardware" media distro system, albeit at a very high price (approaching/exceeding $10,000 by the time you buy the receiver, musiccast box, clients, and upgrae the musiccast's puny 80GB HDD to something big).
What would tryuly be great is when al lthese @#$!% proprietory systems go away and we can just plug any old thing into our network and have full control of it... A Yammy network recevier will control a sony networked dvd player and a panny TV.. and you can control any of them from your fridge!