As the title suggests I wish you could copy one rule of a loot filter to another loot filter because as someone who likes changing my loot filter around a lot I want to be able to also copy certain rules from another filter rather than having to copy it all again, especially with Unique filtering in the game which takes ages to go manually through all the ones I need/want.
I usually just edit the .xml when I want to do that.
You can also use this tool: GitHub - MrReallyYo/leitemfilter-cli
That being said, it would be nice to have a way to do that in-game.