What do you think is the most difficult hole right now (discounting Congressional, which it sounds like will be online shortly)? Try to discount the difficulty of the green specifically at Oakmont, and figure all green speeds are the same.
After a 3 putt within 4.5' at BPB #15, I remain convinced it is the hardest hole in the game. I hit a 280 yard drive with a tailwind, landed my 2nd 25' above the hole, and it rolled down the hill to 4.5' right of the hole, pin high, with a putt that appeared to the eye to break approximately 35', give or take. I played 37'. Not enough, unfortunately. I missed that putt, leaving myself a 3.5 footer back the other way and uphill, which I lipped low, and because of the grade the ball circled the cup and came to rest directly between me and the cup, 3" short. Thus does a 4.5' birdie putt become a bogey. And this is after a 2nd shot that is I think second to SA #17 in difficulty to get anywhere near scoring range on the green. Usually, you just hope to be 12'-16' below the cup at the bottom of the green. My second shot (dunno about the higher tiers) plays usually 130-160, 36' above my lie. If I'm 150+, I'll usually play right into the trap in front, because it is easier to get my 3rd shot close to the pin from the sand than having to play a 5 iron or higher that even with backspin is going to run off the back of the green. Being above the cup is not where you want to be on that green, ever.
I have gone into that hole at -8 and bogeyed it, -7 and double bogeyed it, - 6 and double bogeyed it, and -5 and bogeyed it. Four of those, I bogeyed 16 too. A misadventure there can mess with me for another hole. Usually if I par or birdie it (I have twice birdied it, both times out of the sand), I usually shoot well on #16. So that is my vote, with SA #17 a healthy second. The thing that puts BPB #15 ahead, to me, is that if I am close to the hole on SA #17, which is a hard place to get, I'll admit, I feel reasonably sure I can make the putt. On BPB #15 I can look at a 4.5' putt and go "Dear golf gods, don't let my ball roll to the bottom of the green on this putt."
If you miss a 2' putt there on Championship greens, does it roll off the bottom of the green?
If anyone has ever eagled BPB #15, I'd love to hear about it. Even better, if you have the video, post it. It might calm the nightmares a bit.