I agree that the situation to me (male in my 20s,) seems to have gotten a bit better the last two years. After the guards started patrolling the station has felt safer -- although there were only a handful of times where I have felt actually unsafe and I commute daily. There was a big issue with Moroccan kids smoking heroin around the station in Autumn of 2016, after a number of raids by the police and more guards they all left the station area by spring or summer. It actually gave me hope that these problems can be solved with enough effort. I think the changing of the bus lines has also made Stora Torget into basically a giant bus stop that isn't very pleasant to be in even when there aren't groups of teenagers loitering and smoking cigarettes.