One big hurdle is there seems to be no "deep linking" into a Roku app. I could be wrong there. The other hurdle is that Roku apps don't report back to the OS on exacly what has been viewed.
For exammple, if my last five channels have been...
- NBC: Big Bang Episode 12
- Tablo: Channel 4.1
- NBC: Star Trek Episode 5
- Tablo: Colbert, Dec 25, 2017
- DirectTV NOW: Tennis Channel
...there's currently no way for the Roku to know the history of in-app activity, let alone deep link back to it. Deep linking, plus a history API where Roku apps report back to the Roku OS with their in-app history, would allow for "recently viewed" navigation, like XFINITY's X1 and Google's Live Channels.
This. Would. Be. Amazing!