Kevin's got me when he says, " the general point about the diagonal is that the level of "forced" is variable, depending on how much risk you want to incur."
Forced carries basically don't impact the best players. No one in the US Open will care about the quarry on 18 at Merion. But you can get that player to care about a forced carry if it's on a diagonal because you bring risk/reward into it. A high caliber player can choose to try to carry 250 yards of death if he chooses, but the mere mortal isn't punished by being required to make that same carry--he can choose a carry appropriate to his skill and level of risk tolerance.
Jud, it feels like you're essentially arguing against forced carries of penal hazards. That's fine. I'm only trying to say that if you're going to have a forced carry a diagonal one seems better than the alternative--nothing worse in golf than the small pond in front of the tee that the good player never even has to think about, but that can ruin the hole for a poor soul who cold tops one from time to time.