If we'd let the architecture, not the green speeds determine greatness, a lot less courses would "need our prayers"
If we had more greens that were fascinating at 6-7 speed, we'd have no problems in the heat,be able to maintain firmer,more interesting golf(i.e. every putt would be extremely different i.e. uphill, sidehill vs. downhill sidehill), and FAR LESS costs to maintain.
Today's greens tend to be fast in every direction -therefore far easier to judge.
Oakmont has of course always been an exception (the problem is everyone wants to be an exception-thus the arms race)