Tinkerer.
necromancer is cool, but it would overlap way too much
blood dk= control of blood casting and bone based spells
unholy dk= controlling and summoniong of undead and control of bones
frost dk= frost based spellls of death
affliction warlock= curses and afflictions and deises
frost mage= frost casting spells
demonolgy warlock= summon, command and empower minions to fight for you
beast master hunter= the concept of summoning mobs to fight for you
now abit of overlap is fine, but overlapping with so many specs...
because the engineer is not a class.
where the ^^^ all the stuff above, are classes
if necromancer will ever be added, it will most likley be a fourth spec for death knights, or for warlock.
warlock with shadow infused skeletons and stuff
or just a caster version of Dk, allowing for a new intellect based plate sets