"Necro, Summoning"
Not a good combination.
Necromancy currently ONLY works with frontline fighters.
Unless something changes in Necromancy, there is no saving the Witch Preset.
Pretty sure necromancy works just fine with artillery characters. It healed me when I used my spells at least, when I had it. Like Hail Strike would heal me. The only thing that doesn't heal you for necromancy form direct damage is DOT from the elements.