Attempt to add "Find the difference between edited and unedited post" feature
Any Dev help to add this feature are welcome

( I haven't done it yet )
I actually thought of the same idea just recently! I will try to implement it in the next version release of my user script.
Image tags seem to change within the HTML code over time, so unedited posts with images might be marked as edited. I'm not sure yet how to tackle this.
Hm, maybe comparing only the inner-html of elements instead of comparing the whole html may solve this?