I dont want to be snobbish about this but lets get one thing straight
First off, to be a necromancer you have to be a summoner first.
Secondly, the final subclass choices down the Mage > Summoner line is Necromancer and Conjurer. Summoner will be the most similar to magicians based on what SOE has released on its magic spells. Necromancers will summon skeletal shadowknights while conjurers seem to be featuring humanoid monsters with monk like abilities.