One common use of the "Posts by deleted user" page is investigating vandalism by a deleted user (generally part of a rage-quit), either edits or deletions. If the user doesn't have a lot of posts, that's fine, and we can just open every post in a tab and look at them all. But sometimes, they have a lot:
It would be very useful to be able to sort by last activity to find edit vandalism, and deletion date to find delete vandalism.