So I spent some time on HistoricAerials.Com to look at the changes at BPB. I encourage everyone else to do the same. I looked at Hole 15, arguably the toughest hole out there. It seems like it was built with NO rough. There probably was a fairway/rough cut, but when you look at the 1980 aerial, the rough is obviously so thin and wispy that you can't tell the difference between fairway and rough. Then click on the 2010 or 2015 aerial, and the narrow ribbon of fairway lined by thick rough is apparent.
The design intent of this hole was clearly to test a long, uphill second shot to a tough green complex. NOT to ask the golfer if he can hit a straight drive...
I could not blame Rees Jones or any architect who re-worked the course to add such rough. That obviously had to be the charge from the USGA in preparation for a US Open. I think the greenside bunkers, while re-built and brought closer to the greens, still maintained the original design intent.