I dont understand how this suggestion doesnt recieve more agreement, because frankly nobody in their right mind should want to object to a simple ui improvement that would make organizing and finding content significantly easier and faster. Just make the folders client side only by default, admins can decide if playersfolders can be made public.
However i would like a similar ui improvement to the templates system. I want to be able to open a list of folders, select one folder, and then use my dropdlwn menu in build mode to select only from the contents of that folder until i deselect it. Because crawling through that list also becomes a massive pain.