We're not going to get around the problem of multiple providers of content. The hardware to build the TV's and the connected devices will always be in the hands of giant companies who have a interest in protecting their own selling environment. Google Play will be no different in this way.
Talk has died down now, but the best bet is still second screen as a universal remote. Use a tablet and a service like GoWatchIt to find where the content lives, and then play through the TV app.