I still pick up clothing because I just don’t know whether I got all of them or which ones are missing. Please mark duplicate clothing as such.
I would also be down with duplicates not spawning. That way clothing spawns would get rarer the more you already have and you are on the hunt for that last unique item in your wardrobe! 
This would be a nice feature. I’m constantly getting the same clothing items over and over.
Just don’t think about it and collect them all 
But I dont care much about clothing 
As I don’t click “Take all” very often anymore, I don’t like that option very much.
They could also just pre-select all clothing when you open a container, as clothes don’t take inventory slots and the only reason not to pick up duplicates is to save a click.