Sirens are really dumb and bland, are really easy and unrewarding. I just have spam them again and again until more sirens and then again to kill them all. Maybe their behavior could be improved, they are really slow and just bland compared with other enemies.
On the other hand, the Hidden Sewers felt bad compared with the first time I did the quest, pre-breach. Enemies where placed better, you had to fight with risen archers and axes, now the only interesting enemy is the fat plagued.
I played with a wand and shield, first time I did it with a mace and shield.
Loving the game so far 
Anyone, toughts on this?