It is a big question now how will shadow part of damage implemented. Will it be "out" as one strike or two strikes? If it will go out in two strikes will shadow part get all damage talents again?
2h spec, Black Ice, Outbreak, Desolation, Blood Presence, EP and RoR (assuming 30% mitigation):
Case 1: Two strikes, all talents:
x = 50% * 0.7 * 1.04 * 1.2 * 1.05 * 1.15 * 1.1
y = x * 0.75 * 1.04 * 1.2 * 1.05 * 1.15 * 1.1 * 1.13 * 1.1
PTR SS = x + y = 147.68%
Case 2: Two strikes, no Outbreak, no 2h spec on shadow part:
x = 50% * 0.7 * 1.04 * 1.2 * 1.05 * 1.15 * 1.1
y = x * 0.75 * 1.05 * 1.15 * 1.1 * 1.13 * 1.1
PTR SS = x + y = 129.86%
Case 3: Two strikes, no Outbreak, no 2h spec, no Black Ice on shadow part:
x = 50% * 0.7 * 1.04 * 1.2 * 1.05 * 1.15 * 1.1
y = x * 0.75 * 1.05 * 1.15 * 1.1 * 1.13
PTR SS = x + y = 123.33%
Case 3 makes most sense to me, that means shadow portion won't get affected by 2h spec and Outbreak and we won't take Black Ice and go 12-17 points into Blood instead. So following...
PTR SS weapon damage = (50% * 0.7 * 1.04 * 1.2 * 1.05 * 1.15 * 1.1) + ((50% * 0.7 * 1.04 * 1.2 * 1.05 * 1.15 * 1.1) * 0.75 * 1.05 * 1.15 * 1.1 * 1.13) = 123.33%
PTR SS fixed damage = (317.5 * 0.7 * 1.04 * 1.2 * 1.05 * 1.15 * 1.1) + ((317.5 * 0.7 * 1.04 * 1.2 * 1.05 * 1.15 * 1.1) * 0.75 * 1.05 * 1.15 * 1.1 * 1.13) = 783.13
PTR SS = 123.33% + 783.13
BI Live SS weapon damage = 40% * 1.3 * 1.04 * 1.1 * 1.2 * 1.05 * 1.15 * 1.13 * 1.1 = 107.14%
BI Live SS fixed damage = 317.5 * 1.3 * 1.04 * 1.1 * 1.2 * 1.05 * 1.15 * 1.13 * 1.1 = 850.46
BI Live SS = 107.14% + 850.46
Live SS weapon damage = 40% * 1.3 * 1.04 * 1.1 * 1.2 * 1.05 * 1.15 * 1.13 = 97.4%
Live SS fixed damage = 317.5 * 1.3 * 1.04 * 1.1 * 1.2 * 1.05 * 1.15 * 1.13 = 773.14
Live SS = 97.4% + 773.14 (no Black Ice)
Live OB weapon damage = 80% * 0.7 * 1.375 * 1.05 * 1.15 * 1.1 * 1.2 = 122.73%
Live OB fixed damage = 467.2 * 0.7 * 1.375 * 1.05 * 1.15 * 1.1 * 1.2 = 716.75
Live OB = 122.73% + 716.75 (glyphed, no 2h spec)
Live BS weapon damage = 40% * 0.7 * 1.375 * 1.05 * 1.15 * 1.1 * 1.04 = 53.18%
Live BS fixed damage = 305.6 * 0.7 * 1.37500 * 1.05 * 1.15 * 1.1 * 1.04 = 406.32
Live BS = 53.18% + 487.58
Two BS = 106.36% + 812.64
TLDR:
PTR SS = 123.33% + 783.13 (12+/00/54)
BI Live SS = 107.14% + 850.46 (07/10/54)
Live SS = 97.4% + 773.14 (12+/00/54+)
Live OB = 122.73% + 716.75 (glyphed, 00/10+/54+)
Two BS = 106.36% + 812.64 (12+/00/54)
Reaping may be useful again after all, especially seeing 2xT10 bonus that bumps SS another 10% up to (probably) 135.66% + 861.45 (in comparison OB goes to 135% + 788.42).
EDIT: PvP bonus! BP, Black Ice, no 2h spec.
60% mitigation (plate + shield)
- 3 diseases up
Live: 103.02% + 817.75
PTR: 67.76% + 430.29
OB: 70.13% + 409.57
- no diseases
Live: 79.25% + 629.04
PTR: 31.88% + 202.42
OB: 51% + 297.87
50% mitigation (plate, mail + shield)
- 3 diseases up
Live: 103.02% + 817.75
PTR: 84.7% + 537.87
OB: 87.66% + 511.96
- no diseases
Live: 79.25% + 629.04
PTR: 39.85% + 253.03
OB: 63.76% + 372.34
40% mitigation (mail)
- 3 diseases up
Live: 103.02% + 817.75
PTR: 101.64% + 645.44
OB: 105.2% + 614.35
- no diseases
Live: 79.25% + 629.04
PTR: 47.82% + 303.64
OB: 76.51% + 446.8
30% mitigation (leather)
- 3 diseases up
Live: 103.02% + 817.75
PTR: 118.58% + 753.01
OB: 122.73% + 716.75
- no diseases
Live: 79.25% + 629.04
PTR: 55.79% + 354.24
OB: 89.26% + 521.27
Nerf on anything above leather. If your diseases are dispelled SS becomes junk. Worst of all OB outperforms new SS on every type of armor with diseases and obliterates

new SS on targets without diseases.