I actually am having a lot of fun playing this build running around in Orr and in WvW.
Stacking Vulnerabilities and frequent Death Shrouding and Plague Form helps round it out. In addition, Spectral Walk and Spectral Wall are quite handy.
Yes, it’s a very survivable build but has quite a bit of versatility so you aren’t doing just one or two things all the time.
The Nigh Invincible Build for Necromancer"
I have a full set of Mortal armor of Grenth and use all six Superior Runes of Vampirism.
My weapons of choice are Axe/Focus and Dagger/Dagger.