As Stu mentioned, this was discussed in some depth prior to the move. I appreciate that no one likes having an ability or feature taken away, and as this is a sensitive issue it was not taken lightly. From an administrative perspective, the ability to put a time limit on edits was a very welcome feature. We've been burned in the past by members (manufacturers and thread starters included) going back months or even years later and maliciously editing or completely deleting the content of their posts, rendering important threads useless.
Being able to edit is important—I almost always see errors in my posts right after hitting the 'Post Reply' button—but unlimited edit time can be a serious problem. There are always trade offs, and while it's not a perfect solution, I think the 6 hour edit window is a good middle ground. If someone has a legitimate need to edit something beyond that (making a new post with the updated info may be a better idea since those who've been following the thread won't go back and read the old message) they can ask me via private conversation.