Personally, I enjoy the retaining walls quite a bit. However, it is currently possible to achieve nice "clean" results only by gaming the order of operations. This arises from the fact that a retaining wall oddly interacts with the whole 2x2 area it's placed in despite only being a 1x2 structure (for example). I propose that both dumping into the 2x2 tile containing a retaining wall, and digging in a similar manner only effect the non-retained portion. Otherwise, retaining walls should just be 2x2 structures. Although I like that less, as under the proposal you can ramp up higher / dig down lower will less narrowing every 5 levels. Either way would be more intuitive for planning though. My play-through is a bit permanently effected from having to learn this the hard way. It's probably a nightmare to code, but hey, you're hiring right? =p Love the game. Love, love, love the game.
Dumping & Digging by retaining wall should be "clean" in all situations
I want just one piece the size of the corner piece but without the notch on one corner. Remove the sloped edges and all the other pieces. Make it stackable and allow it to be placed anywhere. (Ignore Terain.) Allow us to drag during placement like the belts and pipes.
I find the current retaining walls mostly useless.
With ~100 hours in, I also found this out the hard way. After placing a retaining wall to go deeper into my iron mine, I had decorated the main area directly against the retaining wall to force trucks to drive versus the ground for maintenance reduction. However, I also toggled the mining designation to be placed on top of retaining walls or visa versa. But while watching the excavators take care of the inside of the mine, I watched as the retained outer portion of my mine disintegrate and my nice roads destroyed because the excavators bucket ghosted through the retaining wall to get the rock and ore from the other side. This proposal would be a nice QoL where the retaining walls were slightly more dynamic or the excavators could detect this "wall" and only excavate on the side that it is currently digging.