I've noticed there's been displeasure with the lack of a true Necromancer Minion Master/Undead Army playstyles and in my tinkering I found something which personally felt quite close.
This build is a combination of the poor man's zombie dog - sacrifice build, with fetishes, and short term minipets(corpse spiders/firebomb/spirit barrage).
I'll start from the top:
First and foremost, I've noticed that channeling spells effectively proc Fetish Sycophants more often(espacially with increased attack speed) due to the nature of how said spells tick. Typically by the end of an area I'll see an army of 10-20 Fetishes.
I personally chose Firebats - Hungrybats due to the high damage(350% weapon damage) and autoaim. While not quite as effective vs large groups the single target damage is excellent and stutter stepping is much easier not having to aim.
Next are the short duration pets:
Spirit Barrage - Manitou does 83% weapon damage per second, stays on you, and has a decent duration.
Firebomb - Pyrogeist does 106% weapon damage per second, has a short duration.
Corpse Spiders - Spider Queen does 42% weapon damage per second, has a decent duration, but does aoe damage.
The great thing about these spells is that you only need to cast them once per fight have long range, and you'll see a nice damage increase with increased LOH/LS.
The Gargantuan is an obvious choice, and rune selection is whatever you feel comfortable with.
I'm sure most are familiar with the dogs:
Circle of Life (with a decent amount of pickup radius on your gear) is perfectly effective at summoning up your dogs, and tagged with Sacrifice - Next of Kin, allows for rapid spamming[of Sacrfice] when fighting large groups to quickly clear the field.
I'd also recommend, if only for the aesthetic value, of equipping a Maximus to your Enchantress as well as a Band of Hollow Whispers(The Haunt spirit almost feels like an extra pet;]) You can also use a Gidbinn, but the Fetishes are so small, don't last long and don't proc nearly as often as Fetish Sycophants.
For your viewing pleasure, The Army:
Just to recap, the army consists of, the Gargantuan, the Zombie Dogs, the Pyrogeist, the Spider Queen, the Manitou, a small horde of fetishes, as well as the Enchantress and her demon.
Feel free to take a look at my WD, he's nothing special, but enough to speed farm MP2~ everything was cheap(50k-2mil per peice).