RE: Although subjectively downvoting posts to zero is anathema to me, the Layer 1 ability to do so must remain (for now at least)

A free upvote to reverse downvotes.

There is a free upvote service from @droida at http://droida.ch/hive/, but I highly doubt that it could reverse the downvote of a whale, let alone a group of whales. At least currently. This project should get much more support from the community. There should be strong co-operation to reverse downvotes.