Windows 10 Universal App
Windows 10 Universal (front end) would provide tablet, PC, mobile, and Xbox access, with minimal UI porting for platforms.
Additionally, voice commands could be built in for use with Cortana. Making the home truly automated.
Second. Small atom-based devices are THE ideal, light-weight way to run the server and if they have a display then they are also an ideal control panel for interacting with the server, but the server UI is not suited to small touch displays. It's such a shame!
I would think it should be extremely simple to port the app so that the front end can be installed on the same machine as the server.