We've discussed a lot of times how to complete SUL migration but maybe we can do it by steps: four years later, I still have to tell users to merge their accounts even in trivial cases.
I think it should be too hard to unify all accounts which:
- can be merged without user interaction (same username and email or password, right?),
- would not leave any unattached account around.
The only drawback I can imagine right now is the very remote case that a user, even if there are no name conflicts, uses two or more local usernames on different wikis and could be automatically logged in with the wrong username. Nothing really bad would happen anyway.
Filing under CentralAuth because I suppose this require a script or so to be written first?