Not sure why this hasn’t been added yet to be honest.
If xat has a smiley for having Allpowers, then it shouldn’t be too far fetched to be able to select them all within the trade app (they must be marked one way or another).
Also seems fairly simple to have the doubles selection - just any power you have multiple of, it’ll add one of each of them to the trade. I’m sure many would find this useful.
I suppose it’s more of a “quality of life” improvement, but I’m sure people still try to remove some powers at the last second.
Overall, I believe it should be added sooner rather than later. It’ll also save the volunteers trouble by not having to deal with those (often petty) type scams.