Even post-nerf, Necrosis is still worth ~1% damage per point (~5% of overall damage). From a single target perspective (ignoring the reduced DnD cooldown), I'm getting Morbidity coming out at a ~0.57% increase in overall damage per point. The talent would probably gain slight value if you find yourself making use of DnD more often.
I ran a sim using 0/3 Morbidity..
167739101 Death Coil Damage over 100 Hours equaling ~9% of the overall damage
With 3/3 Morbidity we see a 15% increase in Death Coil damage (167739101*0.15) = 25160865.15
Increasing total Death Coil damage (167739101+25160865.15) = 192899966.2
Overall damage done over 100 Hours was 1809339202
After factoring in Morbidity % of overall damage from Death Coil (192899966.2/1809339202) = 0.10661349 or 10.7%
% of overall damage from Death Coil increased from ~9% to 10.7% (1.7% increase) from having 3/3 Morbidity
(1.7/3) = ~0.57% overall damage increase per point in Morbidity
Obviously the results will vary a bit and it was based on a sim but I do believe that Necrosis is still worth more than Morbidity as a 51/0/20 build (or close variant).
As far as Best in Slot gear goes, you are going to want to pick up 4 Piece T8 as it is quite good for Blood with the best off-set piece known so far being the
Plated Leggings of Ruination.