I would love this. I rarely use On Now, but would use this a lot so would be great to see last tuned channels in place of On Now as a setting. When I'm watching live TV, I do often like to watch 2-4 shows simultaneously by jumping between them. Currently if its more than 2, then I have to keep going back to the Guide and scrolling to get to them.
What would be REALLY cool as a variation to this, would be if you could swipe up and see the last 4 tuned shows playing 4-up on the screen, then navigate and pick one. I'm guessing that wouldn't be possible.