You keep posting in the faint hope that someone is going to toss you a crumb on this.
1. there are no signs DirecTV will develop a stand-alone 4K DVR. Why would they want to? Their product direction is client server (HS27 etc), to accommodate sat and future IP solutions. Hopefully there will be more timers in the future.
2. "No-one" uses PIP, at least the number is probably too small to be meaningful
For most of DirecTV's customer base, there's nothing wrong with the HS17. Many of the issues posted are not HS17 problems per se, but the growing pains of 4K and in particular HDMI/HDCP. Go back in time and look at the year after HDMI first appeared. Hardly anything seemed to work correctly,