I get reports on either side of this issue all the time -- Pacific is way harder, says one email; the next has it reversed.
Bandon Dunes is rated higher because it's longer, even though length is less of a factor in the difficulty at Bandon Dunes than most anywhere else, because of the run of the ball and the distorting effects of the wind. [It's not so easy to hit a short iron close in the wind.]
Trying to put it all in a formula is pretty much a waste of time, in my opinion. I wouldn't be offended if they took the tack of a couple of courses I know and dispensed with a rating and slope altogether, and just discouraged you from posting your scores when you get home. But the USGA doesn't like such subversion, and they do hold events in Bandon, so I guess they'll keep using their silly formulas.