Battlemage works incredibly well with Arcane Warrior as a tank. Sustaining Draining Aura or Elemental Chaos gives BM/AWs enough area of effect damage to attract all nearby enemies, while Combat Magic and Shimmering Shield allows BM/AWs to survive, along with Stoic to replenish mana drained by sustaining. You should be aware of the damage taken if you plan on using Rock Armor and Arcane Shield (and Miasma). Mana gained by the Stoic talent is equal to 50% of your damage taken. Thus if you are being hit for only a small amount of damage you can run out of mana quite fast, which makes Death Syphon an extremely good option to replenish it.
Another tactic that works is to combine Battlemage with the Keeper specialization. Using skills such as One With Nature in addition to the battlemage skills such as Hand of Winter or Draining Aura, you can deal enormous AoE damage nearby, while you hide back and cast AoE skills such as Inferno fired to break both ranged and melee enemies.