I don't know of a pre-existing tool. Also, it'd be hard to do much comparison in the style you ask without actually parsing the body of the file and normalizing it in preparation for some kind of comparison.
LibreOffice is scriptable from within using
python and javascript. It handles the old MS-Word formats better than MS-Word itself.
Or you could call its APIs via external scripts using its --headless option.
So you could look at LibreOffice for a means of normalizing the document bodies for comparison. Just do it in a way that does not further disturb the originals.