Necro needs some adjustment for better.
1. Mystic siphon damage is really really low and the magic gain is poor. Only slottable for passive damage and passives.
2. Stalking blastbones. Revamp needed or adjust the damage. Sure most of the time pathing is so horrible that it does not find its target at all.
3. Skeletan archanist. Revamp needed or adjust the damage. Slotteble only for gaining passives.
4. Resistant flesh. Remove the heal neft to self or double the protective values or more.
5. Restoring tether. Revamp the hole skill.
6. Ricochet skull. It should be every second cast. If you do not have time just copy Crystal fragments.
Really balancing should not be that hard.