Diagonal bunkers/hazards are nice as they can mostly challenge just about all level of player. Can be one diagonally stretched bunker or a line of bunkers or even a stream. Variable diagonals though, some left-to-right, some right-to-left. Like all things, such a feature can be overused I guess, but are nice in reasonable moderation.
Am I correct in believing that Harry Vardon used diagonal bunkering quite a bit in his designs? Little Aston, Copt Heath, South Staffs being courses connected with him that come to mind.
atb