Problem: There is no easy way to watchlist many similar pages at once, other than adding all of them individually to your watchlist. For example, if I want to watchlist all editions of the Eurovision Song Contest, I'd have to add all 67 of them as well as every new article when it gets created. You can watchlist categories and notice when a new page is added, but that only works if people categorise new pages the way you would expect, and you also still then have to manually add it to your watchlist.
Proposed solution: Introduce a new Special:BulkWatchPages which allows you to watch items by regular expression (with some sane limit), and perhaps other options such as a category. In the example above, the regular expression could be Eurovision Song Contest \d+. Or for templates with subpages, Template:Example(/.*)?. For technical reasons, this would watch every page as if you watched them individually, as opposed to grouping all these pages together as one "watched item". There could also be a Special:BulkUnwatchPages special page so you can un-watch them in bulk, however.
Who would benefit: All editors, especially those who often check other people's edits
