While I appreciate the attention you're giving to pale masters, how about some QoL fixes instead of all the power creep?
1) PMs shouldn't be healed by positive energy. I think having a greater death aura + death aura + lesser death aura + neg energy burst should be plenty. Otherwise, you'll probably see a new tank meta with undead for the immunities and healing + positive healing, which you'll then have to nerf later hurting those who actually like playing PMs.