I think this might work..
Ages back I got a WD Live streaming box for my TV and found a YouTube app nestled away with Netflix and all the 'junk' plugins. I thought nothing of it until I randomly fired it up one day and realized I could 'pair' it with youtube on my phone.
Seems to work in the same way - I browse/select/queue stuff on my tablet/phone and then my WD just gets the content pushed onto it. Doesn't sound that exciting - but was actually quite an enjoyable way to spend an evening with out new video jukebox playing away.
Chromecast seems to be the next step in this process - not just youtube, but 'android' (potentially) as a whole.
Bit that would be really nice, and I assume on Google's radar, is bolting some aggregation app over the top. Say I want to watch a film or program, I search for it. It seems I have Lovefim and netflix installed so polls them. Doesn't find a match then maybe polls your catchup services or amazon prime. Doesn't find a match, then it polls Pay-on-demand services - sky, google themselves etc.
I love IPTV, I love video on demand - but they're all currently in their little silos. Absolute pain in the arse loading an app, searching for something that isn't there, loading another app etc.
Seems a similar concept to the Xbox One, just without the honking great console bolted on - and if anybody can do it, it's Google.