This must have been suggested already, so apologies if this is the case. As the title says, I'd find it extremely useful to have a "remove all" button when equipping characters. I imagine others would agree!
This has already been requested at least a half dozen times. I'll voice my support for the request every time.
Ctrl+click works much better than it used to since it no longer opens and sorts the inventory of the item type being dropped. I'd still like a "remove all" button, but I don't spend many hours per week removing items, so I'd also give higher priority to a "sell-exess" button.