Occultist doesn't mean Necromancer.

Also in 1.0 (pre-class rework), Conjurers cast all the elemental spells including Fire and Blizzard while Thaumaturge could only cast Astral/Umbral aspected spells. Thaumaturge also had a heal that sacrificed a little bit of their own HP.

My question is, why not just rework AST to be this? Casting healing magic builds Nocturnal, giving an attack magic bonus, and casting attack magic builds Diurnal, giving a healing magic bonus.