Based on my experience from what I am seeing is, when a user that does not have edit permissions edits a post they are placed in a queue. Now if there are no moderators on at the time they sit in the queue and when a user is cleaning up some old posts this quickly stacks up.
The issue is now when a moderator now logs in and approves those edits, one after another. The home page is now filled with old topics and questions that a lot of the time are already answered. Should there be someway to possibly alternative from edited posts and newer questions, or space out the approved edits hitting the front page at once?
UPDATE
The issue is apparently being caused by tag edits. Which normally are not a problem but when a mass cleanup is happening, it fills the front page with old unanswered questions. The possible fix could be to disable tag edits being brought up to the main page. The other option possibly is when editing a tag, give the option to the editor if the post should be brought to the front page?
Listed below is a screenshot showing the issue.