Alternate Abilities:
Frozen Device -> Subterranean Assault (for more add control - note you should move Warhorn to the main bar and put Eternal Guardian on the backbar for the passive regen if you decide to use this)
Reviving Barrier -> Healing Thicket (for the extra magicka regen from the support line passive)
Northern Storm -> Healing Thicket (for the extra 8% max magicka)
Gripping Shards -> Shimmering Shield (for fights where there are few or no ranged adds)
Inner Beast -> Inner Rage (choose the morph based on resource preference)

Vampirism is not required but is recommended for the passive regen and low health mitigation bonuses.