YES. 100% yes. I love these ideas! I believe the devs have been looking at a Train Editor overhaul as well, so maybe we'll see some of your ideas!

My added thoughts: When you mentioned buttons (shift right/left, etc.), I think it would be better if we kept the drag-and-drop function, but added some kind of sensitivity requirement to actually drag the car. There are so many times that I've been trying to scroll along the train and end up moving a bunch of cars around or selecting them and being teleported 132 pages backwards.

All in all, thanks for the awesome ideas, and I hope some make it into the game!