Good thread, you should send your feedback to Larian through the official form so they can process it. One thing I would like to point out is that Tyranny has a fear and loyalty system for companions that works like what you suggest. Instead of approval and disapproval you build up two independent meters that interact with each other. You can even get companions to stay with you out of fear in Tyranny.
I've sent my feedback to Larian directly too, of course. I hope they actually bother to read it.
Regarding Tyranny, I'm not very fond of how it was implemented because you cannot fail in keeping your companions together. If you treat them badly then their "fear" grow, if kindly then their "loyalty" grow. They stay with you in any case. I actually liked PoE 2 dynamics with characters, where besides your own reputation they had reputation towards each other and a whole bunch of different moral values. And no matter of your reputation, certain actions cause your companions leave of even become hostile.
Dragon age 2 actually did something similar but I think it was actually very good. The only bad way to treat your companions in da2 was to ignore them completely. Unfortunately I can only think of one instance where it had actual consequences. Man this game had many interesting ideas. I wish they had more time to develop it