Edit watched status by date (in case of client glitch)
A misbehaving client can quickly mark thousands of movies or episodes as marked, incorrectly. To undo this takes considerable manual time. Since an error like this occurs quickly at once, there should be an option to unwatch everything watched on a specific date. This would allow a quick and easy solution for a major issue.
(In this case, I believe a dog sat on my keyboard. By hitting "W", it marked hundreds of movies as watched, wrongly.)