After playing a bunch of pacifist runs, I can honestly say that the flying drones are the one to fear. Mistakes with (and especially without) a gun are tremendously more likely to cost you your playthrough.
From the pacifist runs, you can quickly get a grasp of the turrets weaknesses besides the obvious rotating blind spot. By chasing blind spots or sprinting past across from their line of fire, you really can skip 90% of turrets to get where you want to be.
Heck one time I'd ran out of bullets on an ordinary playthrough and didn't feel like dealing with the stress of finding more so I jumped in sight of a turret and stood completely still, only opposite ends of a corridor from eachother. Every shot whizzed past my ears until after a few tens of rounds it simply stopped firing for good. I wanted to die but the powers that be wouldn't let me.
But man, those tasers never seem to get easier. The things I do to successfully avoid them. So hit or miss. Hard to tell whether I should call it skill or luck.