Maybe it's as simple as having a changelog on titles. If a mod changes the link or title, you could show something to indicate that on the frontpage, and on the comments page show more details like what the original link/title was, and what it was changed to, and by whom.
IOW it seems like transparency in moderation is what you really need. This would also solve the problem of original discussion referencing the old article no longer making sense when the article changes.