This new set should incorporate a 7th piece of equipment, that 7th piece should be either a Phylactery or belt. A 7th piece will help with other custom gear equips.
Another amplifying gear piece should be a specifically designed Bracers, that can give boost to the skill set. Bone Spirit should benefit a lot from this set as it is one of Necromancers, most potential but useless skill.
Necromancer needs overall more gear, one handed scythes and phylactery’s.
Lastly, maybe consider remodifying overall damage. Instead, do a stack like for every bone spear or bone spirit casted, you gain a stack that last 5 seconds increasing damage by let’s say 2500%, stacking 5 times. Keep Simulacrum’s damage the same at a triple amount increase.