A couple of nights ago, something wonderful happened. I took the phone off the charger, and the battery drain issue was gone. While not in use, my 950 consumed around 2%/hour (which is fine), and 10-15% while running Edge (also fine). I
had a great phone again, just like the other low-end Lumias that I have owned previously that only needed charging every other night, and this lasted for about a day. Then I was back at 5-10%/hour idle consumption and 15-20%/hour when in use. I was a wall-hugger
again.
Since then, I have seen this pattern of alternating between acceptable and unacceptable numbers, without being able to pinpoint what triggers the transitions. It doesn't look like a hardware problem, but it's really difficult to tell. The only unusual thing
that I did just before the phone got those fantastic power consumption numberswas to accept a Wi-Fi Sense prompt that wanted me to authorize Facebook. I hadn't seen this prompt on that phone before, and when accepting the access request, it looked to me like both the Facebook and the Settings apps crashed. It could be that something
really did crash in the background too, causing a sharp drop in power consumption, or it was just a lucky coincidence, and the Win10 UX team is no longer even trying to implement transitions that don't leave you
confused and scared.
In the (now) weeks since the reset, my 950 has remained stable, getting at least 17 hours of life with fairly regular data use, although no phone calls. From what you describe it sure sounds like some issue with the wifi radio, although whether hardware
or a driver is a good question.
I do not use any kind of Wi-Fi Sense, as I have found such schemes to be pretty buggy (and got tired of having to turn wifi off and on to get apps to realize it is there).
To compare, I upgraded my old 920 to WP10. It has a similar app list as my 950, but no SIM. Sitting on my desk it will go three and a half days. My old 800, on WP7.8, OOB app load, no SIM, sitting on my desk, has gone for 4 days and is still at 63% battery.
So I think the 950 still has some optimization to be done.