TL;DRPut multiple items to a single quickslot, scroll through them like a blueprint book
What ?Blueprint books allow players to scroll through multiple blueprints on one quickslot. This is bonkers convenient and feels amazing.
Let's do that, but for individual items (inserters, power poles, belts, train things, etc)
Why ?This differs from blueprints because placing individual items in-game behaves differently than blueprints. In the case of trains, there are automatic orientations for signals based upon the rail's orientation. Also, splitter ghosts cannot be placed on pre-existing belts. I'm sure there are more.
Here's an example of vanilla blueprint book behavior
And a mock representation of the idea (note, individual item blueprints do not behave the same as placing objects as noted above)
It could be implemented the same way blueprint books are, just with another class of planner (so to speak).
This would allow sharing between players and saves much like the current BP book system.
Incidentally I just found OSHA Hot Swap that provides similar functionality. Best devs/modders ever.