I've never considered the idea of an 'ideal height'. I think the best rough gives a player options and temptations - isn't that what good design is all about? If all you can do is hack a wedge out sideways, that seems pretty boring to me.
Plant the thought that the player might be able to clear the hazard up ahead, or even go at the green. The heroic shot well executed might come off, but the less than perfect shot will be punished.
I also concur with the comments about flying lies, as these create a more exciting risk/reward element, with the opportunity to play to the pin weighed against the possibility of an airmailed green, which usually leads to a far worse fate than a lay-up short of the green.