JES,
For all the talk of the Golden Age strategies, as near as I can tell, good players today focus strategy more tightly on distance, trajectory, and spin control and how those can take advantage of green contours to get close. I don't think they even factor outside bunkers in, although they would factor in water.
Generally, I have come to believe that for good players, challenging on the Sunday pin with bunkers outside the putting surface just isn't enough. Putting the challenges inside the putting surface is what is required, as they are that good. Obviously, if you have moderate distance control and accuracy, playing for the middle of the green probably makes more sense. Most average players should do this anyway, as their strategy should still be to avoid bunkers.
I agree with your point to a degree. One reason I generally limit my two tier greens is because those tiers can take a shot and kick it back 40 or more feet from the pin, when the ball landed just a few feet short. The rolling edges I mostly use are more gentle and generally don't kick the ball back that far, just stop it in place, but I guess that depends on total spin, etc.
Providing that those rolls don't reject your shots off the green, is the risk all that much greater? You have a chance to get close, and a chance to be further away. If you aim at the middle, you only have a chance to be somewhat further away.
In terms of risk, is that any greater than, say, going for a green on a par 5 in two? At 220 yards, and with a pond near the green, you have a chance at 4 and a chance at 6 or 7. On a par 4 with a rolling green as described, aiming at the middle says you most likely make 4, but being bold gives you a chance at 3, a probable 4, and at worst 5, assuming you generally are a good lag putter.