Actually touched on this topic last night at dinner with my son, a good golfer. Our home club is 6700 yards, which he and his former college golf buds could overpower, but usually don't.
Basically at that length, if the pins are easy, they shoot 60's (he shot a 63 in the club championship, for example) but if put in tricky positions, its still hard to break 70.
Based on that, I suspect greens might be designed differently, with more tucked pins if a club was interested in protecting par, and more contour than the typical 1.5-<2% cup areas to keep the challenge up a different way. And, maybe the pins would be even closer to the fringe than they already are!
Some clubs would protect all the greens and fw better, maybe in the RTJ 50's style. I believe any chance of wide fairways would be greatly reduced, as golf implemented the old US Open strategies to protect par in light of effectively reduced length. I mean, if there were other strategies to counter effectively shorter courses, I think someone would have come up with them by now, so I think we have sort of seen what would happen in general, but it might be even more exaggerated.
Interesting, because its not out of the realm of possibility that somewhere, courses are mandated to take out turf to conserve water, and many might simply reduce yardage, taking out back tees that hardly anyone uses anyway. So, for different reasons, this could still happen somewhere and it would be interesting to see the real world results.