Nick, The rankings don;t matter as much as quality does. If one supposes that the rankings mimic the quality of the courses then that person knows very little about the ranking system and the people who make up the panels.
Openness off the tee doesn't mean the driving zones are not tight. That's what makes some courses so great. They appear to be "hit it anywhere" when in reality that openness is there to confuse the better golfer by NOT giving him the exact line to aim. The golfer therefore has to learn where the proper spots are, when the line is not dictated to them.
This is part of the genius of ANGC and other great courses that embrace this principle. It is also the flaw of some great course that have covered their hallowed ground with unneeded and "stupid rough".