Here is a totally new build for the Necromancer, that should be powerful enough as is to compete with the LoN Thorner:
The build is based on the gem: Legacy of Dreams, while we are wearing the Blind Faith helm.
The Blind Faith will be totally reworked, since it's an instant salvage right now.
Blind Faith: "Whenever you cast Bone Spirit, all your revived minions cast Bone Spirit on the same target. Revived minions last twice as long."
The Phylactery, gloves and shoulder can be any item you wish.
This opens up another building path and massively improves the useless Blind Faith.