It happens quite regularly that some enthusiastic user goes ahead and fixes some problem with a tag and edits a lot of posts in a short time. This can have a very negative effect on the front page of a site, especially on slow-moving sites. These mass-edits displace new questions and answers from the front page that need the attention with a lot of old posts, where nothing except one tag changed.
Many experienced SE users know about this problem and space out their edits to avoid breaking the front page, but not everyone does it. I propose to at least warn a user if a significant number of posts on the front page was already edited by him (e.g. 10 out of the default 30) and he's trying to edit another old post. Another option would be to outright block edits on old posts from users that have too many posts edited by them already on the front page.
This won't solve the difficult problem of large-scale edit and tagging operations, it is meant as a way to educate those users about the problem of a large number of small edits in quick succession. Those users are usually enthusiastic, they try to make the site better, they just need to be told how to minimize the negative effects of their actions.