Total speculation based on thinking about this for 2 days.
According to DirecTV, certain Samsung 2011 HDTV models (D6000, D6400 and D6420) are RVU compliant. All 2012 & 2013 Samsung SMART TVs are RVU compliant.
The 2014 Samsung UHDTVs are SMART TVs, so it seems logical that these Samsung TVs would need to run as an RVU over the network to get 4K programming, bypassing HDMI UHD Color connection.
It would seem most likely that this would not support a linear channel (though I could be wrong), but only streaming 4K VOD using the Genie as a passthru for internet data, as HEVC is not available in the Genie, unless DirecTV plans to use .h264 for linear channels, which I doubt they have the bandwidth to use (but they could surprise us I guess).
Given ESPN was burned on 3D, as was DirecTV, I imagine they will be more conservative in UHD linear channels this time.