It seems these are complicated issues, so maybe it's better to look at
small steps in the right direction, rather than something that will solve
everything at once. i.e.
* Have people stop committing other people's translations under their own
name, instead only use something like a bot account, that obviously isn't
taking credit; maybe even better if the bot could do a commit per
translator, and list the translator in the comment.
* Have an easy interface to go from a special page -> system message, such
as a hook that would allow rendering the page such that each message is
marked, and links back to somewhere useful.
* Try to generate some kind of "what links here" for messages. Maybe use
a maintenance script to generate each special page, so the message
function can log the page/message; render examples for extensions from
their parser tests, etc.