I just had an idea about aligning your items to the hand spots in the inventory menu. So it’s an idea, and not really a necessary change. But, it would reduce the input method via controller or mouse by one click:
So click on an item and keep holding the button while dragging the item to the destination slot. Release the button and the item falls into place.
A visual treat, in order to indicate that the item is being moved would be - duplicate or triple the curser arrow from the beginning slot towards destination slot. With beginning the arrow being smallest up to regular size at the destination slot.
Again this is just an idea which came to my mind, and if would make things easier is on another hand.