Not really. I'm a NB caster/healer hybrid (have been since launch) and I'll be dropping Vampirism. Aside from the ult, the skills are cumbersome to use and a waste of a skill slot in many cases in order to get the regen bonus. Even the Drain Essence buff that's 3 seconds you're vulnerable and doing weak damage when you could instead heal up by other means. Mist Form conflicts too much with Funnel Health, Sap Essence, and Rapid Regen- especially considering you can instead Dark Cloak to escape instead. Even Devouring Swarm is taking a hit with healing being nerfed across the board in PvP.

I'll likely be going back to Bolstering Darkness for 60% raw mitigation for 14 seconds (with a nice ally Synergy bonus) versus some damage and healing w/ Swarm over only 5 seconds of easily avoidable AoE.