Herculean Trousers also have 4 STP.
Perfect Samnuha Trousers are usable by the exact same jobs as Herculean, and have STP+7 TA+3% DA+3% Acc+15 DEX+16 (effectively Acc+27, the exact same as these Herc Trousers). These Herc obviously have a nice augment to allow them to fill some of the same kinds of roles as Samnuha in case you don't have those, and the Atk+36 is a nice perk if you aren't capped, but Samnuha are still gonna be better.
Anyway, this Herc augment doesn't require Dark Matter and the poster said it was from a Fern stone, so I'm not even sure why we're talking about it so much here (other than to say spending a ton of time trying to augment Herculean legs as melee TP gear might not be the best use of your augment chances).
Let's talk about why we're REALLY here. Kick *** DM augments from Oseem like this one I got today: