The current way sorting Collections is tedious and I've honestly stopped bothering to try and organize my collections, since there are too many items to sort them by moving the items up or down the list by one space.
Steam's wishlist lets me grab an item's tab and drag it to where on  the list I want it, and on top of that, there's a little text input that lets me select a position in the list to put it without having to drag it at all.
No need to implement both methods, even just one of these would be much better then clicking for half an hour to organize a mildly sized collection.