Last modified: 2006-09-14 14:16:42 UTC
The watchlist table should map users to page ids and not to page titles and namespaces. This would make the system more efficient because you wouldn't have to update the watchlist whenever a page was moved.
Not so; you still have to add the redirect, and this would make it impossible to watch deleted pages (so things would fall off the watchlist on delete/undelete). This is why it was changed from ID numbers to titles.