Yep. It scales way, way too good not to be. You could completely ignore the +360 damage from its debuff and it will still do more damage than SS. Let's do a bit of math. We'll say S2 sword and 2500 AP (easy to get in a raid).
Hemo: (254 + 2500 / 14 * 2.6) * 1.25 == 897
SS: ((254 + 2500 / 14 * 2.4) + 98) * 1.06 * 1.1 == 910
So, at 2500 AP, SS outdamages Hemo by
13. 5/5 Lethality will skew that a bit towards SS, but not by a whole lot. Remember, that's also completely ignoring the +360 damage from Hemo. Now, how about a comparison geared a bit more towards Hemo?
3500 AP, weapon is
Syphon of the Nethrazim.
Hemo: (280.5 + 3500 / 14 * 2.8) * 1.25 == 1225.6
SS: ((280.5 + 3500 / 14 * 2.4) + 98) * 1.06 * 1.1 == 1140.9
Completely and utterly owned. Nearly a 100 damage lead before the debuff is considered. Let's do a bit more math to see how Combat Potency factors in. We'll assume the best case scenario for SS, and say we're using nothing but SS or Hemo, and that we have a 1.5 speed offhand that never misses. CP generates an average of 3 energy per offhand hit. With Slice and Dice active, our offhand attack speed is 1.15. So, we gain about 2.6 energy per second in this best case scenario. Hemo can be used every 3.5 seconds, SS can be used once every 4 seconds before CP, and once every 3.17 seconds with. Now, to build our attack table, get our average values, and computer DPS. We'll say 35% crit (a bit on the high end, but we're going with best case scenario for SS).
Normal Hemo: 1225.6
Crit Hemo (1/5 Lethality): 2524.7
Average Hemo:
1225.6 * .65 == 796.6
2524.7 * .35 == 883.4
---------------------
Average: 1680
Normal SS: 1140.9
Crit SS: 2624
Average SS:
1140.9 * .65 == 741.6
2624.0 * .35 == 918.4
---------------------
Average: 1660
So, without factoring the 360 additional damage from the debuff, Hemo outdamages SS by 20. Now, DPS.
Hemo DPS: 1680 / 3.5 == 480
SS DPS: 1660 / 3.17 == 523.6
So, SS beats hemo without the debuff. What about with it?
Hemo DPS: (1680 + 360) / 3.5 == 582.8
So, there we have it. The numbers don't lie. With high end raid stats, and a crit rate heavily skewed towards SS, along with perfect Combat Potency proccing, SS loses to Hemo by nearly 60 DPS. I think we have a clear winner.