I don't disagree with your perspective. If it were a movie made today, I'd be a lot more touchy about it. When I saw GWTW for the first time, it was in the 60's and I was 12. And the attitudes about men and women relationships hadn't changed all that much yet. Hell, I was still doing everything I could to hide my good grades from the boys, because no one wanted to ask a girl smarter than them on a date.
And you'll probably take this the wrong way, but sometimes when you are a powerful woman, it's nice to meet your match, someone as able as you to hand out the shit, an equal. Rhett and Scarlett were both powerful people. They fought like powerful people. He won that round and he obviously didn't hurt a hair on her thick head. I don't recall anything in that movie that leads me to believe they were in a typical patriarchal relationship.