You say that the original plans were more, but there really wasn't much. The only big thing we can point to is Woody's Round-up, which likely would've only been a M&G anyway.
The rockwork would've just been unnecessary imo without actual show scenes on the ride. Sometimes you've just gotta call a spade a spade - Slinky is nothing more than an exposed "junior launch coaster", as Mack describes it.