Deleting a page is a serious action but it's easy to accidentally pick a wrong reason from any pre-supplied choices on offer in the dropdown menu. That mistake is then frozen into the logs forever. It should be possible to revise a deletion log entry. This would require UI for:
- Editing the log entry (probably copied from the existing deletion interface)
- Displaying an indicator next to any entry on Special:Log/delete that has been modified
- A new log for revisions to any given log entry.