I'd bet most of those old features on the really old courses, particularly if they were inline with the direction of a hole were done for drainage reasons. You're all calling them dykes but I bet originally they were ditches and dykes.
Originally they probably just shoveled out a ditch and piled the dirt on the side as they went along which became the dike. Because of the tendency of sheet drainage water to bring dirt and silt along with it the ditch part of most of these old features has probably filled in over the years to become almost impercible now.
Oakmont has a number of these open inline drainage ditches on some holes and they sure do get in the heads of players if you stray wide of the flanking bunkers. I bet those ditches are original to the course which don't forget was begun in 1903.
Personally, if this type of feature was used today in new construction I'd keep most of it either inline with the hole or use it as a slight diagonal and do it with the dike or grass covered wall and not the depressed or sunken ditch. If you turn these features dead perpindicular to the line of the holes then they become an architectural feature very reminiscent of the old "steeplechase" style of architecture that included the perpindicular cop bunker and such.
This type of thing, in my opinion, was the way of early rudimentary inland architecture just after golf and architecture left the linksland. It was a form of golf architecture fairly closely related to the world of recreations to do with the horse which back then was the basic mode of local transportation anyway so it was not illogical for those people building inland courses back then to create features very reminiscent of the world of horse recreation and horse related sport such as steeplechasing, foxhunting, horse racing etc.
Should this type of basic rudimentary feature be used again in golf architecture as it was over 125 years ago? Golf architecture seems to be looking back to the past bigtime these days so I see no real reason why it shouldn't look even that far back again. Will it be accepted today? Who knows. The only way to find out is to try it again and see.
PaulC:
Cancel those that big machinery that carts huge quantities of earth and file all over the site on the Maryland project and just bring a couple of hundred shovels and a ton of immigrant laborers via President Little Shrub's new immigration proposal.