Kripp's Gigantic Minion Army Infernalist

NEW in 0.4 - Passives were reshuffled, allowing Witch to be in closer proximity to more minion nodes, but this means that it is no longer worthwhile to chase armor nodes.

NEW in 0.3 - Support gems now being usable multiple times allows you to play many different kinds of minions, and buffing their damage significantly through Muster and Gigantism (passive). Elemental Weakness now debuffs all resistances, and minions can break armor from passives - you really just play any minion and it's great! Minions received a nerf in AoE damage, but the Infernal Hound had its radius increased by 67% (this is 180% MORE area), covering that new weakness.

Leveling:
Level to 25-30 with Essence Drain + Contagion. You can still get minion passives, just the ones that also grant spell damage. If a monster dies while affected by Contagion, and you Unearth its corpse, it will spawn an Unearth minion that will apply the same stacked DoT on each hit.

While leveling, get enough Int and Dex to be able to use your gems, and the rest in Str for extra health. Don't be afraid to respec these stat nodes if your gear changes to meet new requirements