They're never going to "fix" it for your saves. The fixes they have done only work on new games.
That's not true. If they take an item out of a cell or out of the game entirely all saves will be affected by it. The items and objects in games can be thought of as "instances" of the original object. If the original object changes, the instances change. But you can change the instance without changing the base object.
The only thing they can't do is undo things like items falling through the floor or items disappearing.