On my iPhone I have a folder called MyHidden. I put all my pictures from the Hidden Album into it. It will look empty, of course. If I unhide the Hidden pictures, they'll show up in MyHidden. If I want them hidden again, I just select-all, and they're invisible again, except in Hidden.
Then I can put all the pictures of My Ex in the MyEx album-- it will also appear empty. But if I select-all in Hidden and unhide, then MyEx will be filled with my ex. MyHidden will also have all my Hidden pictures, so I can select-all and Hide, and all the pictures will be hidden again. I can make another album for MyOtherEx, and so on.
You just have to make sure that ALL of the pictures in Hidden are in MyHidden, or you lose track of them when you unhide them.
Otherwise, you just have to hope Apple acts on your suggestion. What do you think?