I second (again) the need for a plotbunny foster home/abandoned work amnesty clearinghouse. I've seen big works deleted because the author was nagged for their WIP and no one thought to step forward and offer their help.

AO3 sort of already has the framework. The 'Inspired by/re-mix' option links works together but at the moment it is one way. From the new work I can easily find the original, but the original doesn't link to the new works. It could be done manually but if it was automated there might be less chance of links breaking when other random internet glitches and changes occur.