Gibson's movie would have been MUCH better as a straightforward story about Francis Marion.
I like movies that portray history as it actually happened. One concern I have with the Gibson movie was the scene where the movie's Col. Tavington (a stand-in for British Col. Tarleton) burns people alive in a church. Tarleton burned farm animals alive in a barn, not people. However, some British and their Indian allies did burn people alive in their cabins in Pennsylvania during the war.
I guess it is movie license to throw facts into a blender and show on the screen whatever comes out.
I'd be happy to see a movie on Francis Marion. Wasn't there an old Disney TV series about him? Of course, Disney has gone on to make far less wholesome movies these days.