SS is overall just a problem because
a.) It is tied to critical hits and not only pushes the crit-meta (more crits equal more damage), but also heavily favour heroes who get passive crit bonuses, while penalizing slow weapons. If you have 20%+ crit chance, you can have SS up pretty much all the time in a horde (where you need it the most), even with slow weapons, while at 15% or lower, that is usually not the case.
b.) It has by far the highest utility of all traits, mainly because all other traits are too situational and do not provide much benefit in those situations.
I know that this has been discussed ad nauseum. What’s funny is that for carreers with two melee slots, SS becomes even stronger, simply because you can gear one weapon as your mean damage dealing tool and your other for another purpose. This is especially true for GK, where you can put parry, opportunist or off-balance on your shield and pretty much get the benefit of that trait while not having to forfeit your access to SS. Put off-balance on your Bret-S&S with maxed out BCR, let the horde hit you once, bash, light attack, take out great sword with SS, kill everything. Once SS is up, you can take out your Bret-S&S with increased AS and use charged-light-charged to absolutely demolish armoured targets.
Point is: We need more traits that translate into more damage, but in different ways.