We may not know anything about murder mechanic right now (I personally would like it to be removed, but a lot of people seem to like it for some reason), but we know that Scheming trait from AA2 is making it's return and it seems to be improved. In AA2 the trait just increased interaction success chance on characters with Exploitable trait. In SVS Exploitable trait is no more and we see in one of the trailers green haired girl is saying something like "I know your little secret. You know what it means, right?" after player character cheated on his girlfriend. So it seems characters with Scheming trait will have actual blackmailing mechanic and not just increased interaction success chance.
What I'm saying is even though some things definitely seem to be downgraded or removed, I can see plenty of things being added or improved.