don't know whether this was considered before, but what about the possibility to change items (belts, factories, ...) automaticly?
example: one yellow belt surrounds my entire base (behind the walls) to feed the gun turrets with ammunition. Now that the aliens attack my base every two or three seconds, the yellow belt isn't fast enough in some situations. Red belts would be better. It would help a lot if I could change the yellow belts into red belts just by giving an order to my robots. To do this manually would take ages. Same (but not that complex) is to change grey factories to blue or blue to yellow. Yellow inserters to blue, ...
It could work like this: You press a button and a small window pops up. There you can choose what item "X" has to be replaced by the item "Y". In the next step you can choose if you want to replace all items in your base (e.g. change all yellow belts to red belts) or if you just want to change the items in a certain area (could work like the deconstruction tool for robots).
