The majority of players are bad and they don't care to get better.

Most DPS jobs in this game are very straight forward, and can easily be figured out with a simple reading of tooltips and common sense. However most people just don't care enough to give even that and will just hit whatever button looks the coolest.

No amount of hand holding or feedback will fix people like this, I bet none of those terrible DPS you see in duty finder have even done SSS, or maybe even know what it is. Same would happen if they added more things. So I believe SSS is plenty.