I dont think remote play can or willl ever be a killer feature.
Yes it can be innovated, all sony has to do is make some sort of controller/cradle thing to hold your phone or tablet while connecting via bluetooth and its sorted.
The real issue will still be that you have to buy two devices. The console and the host device. Now if we are talking about doing all this sans console then thats a different thing. That's PS now, and thats a totaly different kinda problem. Then we will be talking about subscription services and how long of a delay between physical and stream releases.