To me, a downvote usually indicates a problem with an answer. When I downvote it's to mark the answer as having a problem, not the person. If the answer is fixed, I want to remove that downvote - but it's tricky to keep track of all the questions I've looked at over the last few hours.
I don't actually downvote very much, but it's very easy to forget what's going on.
It would be nice to have some way of indicating in an edit that you (the editor/answerer) believe the reason for the downvote has now been resolved, so that the downvoters could come and undo their downvotes or explain why it's still not fixed.
(Note: this isn't about rep-recovery, but quality control. I would feel a lot better about downvoting on "iffy" answers if I felt it was like that the answer would be fixed and I could undo the vote. Whether or not I'd get back the cost of the downvote is somewhat immaterial.)