So I was crunching some number on the new sets, and I think Draughr Hulk and Essence Thief may be BiS for Imperial Stam DPS (any class more or less).
Here is the math.
Each Stamina is worth 10.46 weapon damage in terms of DPS
Imperials get +10% stamina, which means a normal set stam bonus is 1063.7 instead of 976, the Draughr Hulk 5 piece bonus is 2750 instead of 2500.
So 5 piece Draughr Hulk is effectively 568 weapon damage (5942 stam total / 10.46). This makes it the best non-conditional damage boost.
Hundings is effectively 401 Weapon damage (1064 Stam (102 effective weapon damage) + 299 weapon damage). It also gives 6.3% crit chance of course.
Automaton is 231 effective weapon damage all the time (129 + 1064 stam), plus 400 for physical damage. This is better than Draughr by only 63 effective weapon damage, and probably comes out behind for most classes that include non physical (poison etc) in their rotation.
Essence Thief is effectively 333 weapon damage (1064 Stam (102 effective weapon damage) x2, 129 weapon damage), plus the proc. If you assume that you light attack 1 time per second, it procs about every 7 seconds. It lasts for 10 seconds, so is active ~60% of the time, so you can probably calculate it as ~7% overall damage increase (12% increase 60% of the time). Of course also has a nice little health and stam recovery.
Draugr and Automaton have the best non-proc damage at effectively 799 overall and 1199 for physical.
If you include the proc though, and assume base weapon damage is only 1200 Draughr + Essence Theif is effectively 1048 with no conditions (901 effective weapon damage + 1200 base * 7%), and this doesn't take into effect better weapons (so more base weapon damage), Major Brutality, or any other buffs, all of which Essence Thief stacks on since it's just a bonus to damage done.
Draugr + Hundings is pretty good too, with 1069 unconditional effective damage increase + some extra crit, also crafted, so 500 runs of Direfrost or White Gold Tower for that sharpened weapon
, but it lacks the stam and health recovery and is otherwise pretty much the same as essence thief.
So seems to be, unless the essence thief proc is broken, or the damage multiplier is not what I expect, that is better than pretty much anything else
Comments before I start farming Essence Thief
? Are there soft caps on the bonus damage from Stamina? If so this become terrible.