I really tried to make a Bleeding Caster work…and when I thought it might be “okay”, I looked around and saw what can be achieved with the same skills and Vitality. So: 
@Nery:
1 mastery might be enough (especially Occultist, which gains no real Bleeding Support), because you can always get 57 from Devotions with Revenant and Huntress. But it would be really interesting to make them not both mandatory…I skip Revenant where I can nowadays just to play something different.