Something off brand and unique for a necromancer would be introducing a Rifle or a Longbow, giving them better dueling capabilities and less obnoxious area crowd control. Currently the best necromancer builds are all aimed towards crowd control or area condition damage. There is an exceedingly low ability to duel well, this comes from a lack of any kind of invulnerable evade invisibility or block. So I propose the Deaths Harbinger with a rifle and to stop this from being ridiculous remove lifeforce transform and replace it with a single lifeforce skill shot.
Necromancer - Deaths Harbinger Weapon Skills
1 Grenths Bullet: 5 + life force 3%
2 Deadly Recoil: 3 + daze + evade backward.
3 Skyfall: 2x5 ranged area damage + 1% life force per strike
4 Underworlds Reach: 7 + 10% lifeforce
5 Unholy Haste: 3 + evade + finisher leap + quickness
Life Force Attack - Grenths Claim: 9 +finishes downed, line missile, consumes all life force.
utilizing deceptions inherently given to thief
heal - Messengers Path: heal 6 and gain invisibility (3 seconds)
utility - Bringer of Bad News: inflict vulnerability and Reveal in a targeted area. gain 2 life force per target struck. (4 seconds)
utility - Dark Tidings: create a smoke field that inflicts poison and breaks stun (3 seconds)
utility - Barrel of Death: your next 3 attacks will critically strike. (5 seconds)
utility - Dont Shoot the Messenger: remove conditions and gain boons.
elite - Six Feet Under: 6 + knockdown, attacks against this target will give allies quickness for 2 seconds (marked 3 seconds)