In short, evil path needs A LOT of work. I made a very long post about it but nobody reads it because it's a very long post. Here's the link if someone else wants to read https://forums.larian.com/ubbthreads.php?ubb=showflat&Number=716608#Post716608 TLDR version is that you can roleplay only a "stupid evil" alignment or a murder hobo at this point of EA.
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.
Here's the link if someone else wants to read 
