I have a 58 WD in Act 3 Hell, and I have been using sacrifice since level 19 or so.
Once you unlock the Gargantuan (lvl 19?), Sacrifice becomes a viable way of doing massive damage (since you don't need the dogs for tanking). I use the following skills:
- Summon Zombie Dog with Final Gift (15% chance of leaving a health globe at death)
- Sacrifice with Next of Kin (35% of spawning additional Zombie Dog at detonation)
- Soul Harvest with Soul to Waste (extends duration of Soul Harvest to 60 seconds)
- Summon Gargantuan with Restless Giant (enrages at bosses)
Left Click. Firebomb with Fire Pit (creates a pool of fire that does damage over time)
Right Click. Grasp of the Dead with Death is Life (5% chance of leaving a health globe)
Passives: Zombie Handler (+1 dog and +20% Gargantuan health), Pierce the Veil (+20% damage, +30% mana cost), and Gruesome Feast (+10% max mana and +10% intelligence at health globe pickup)
With regard to strategy, the Gargantuan is a tank and the Restless Giant is awesome against powerful enemies. The Zombie Handler passive gives him more health. Also, the Pierce the Veil passive is great for this build because mana is not an issue for the skills and the increased damage is helpful.
Step 1: Try to enter a fight with Zombie Dogs in tow. This isn't a must, but the build is centered around a mass Sacrifice attack. (If you don't have any dogs, skip to step 4 until cooldown is done.) Run into the thick of the enemies and use Soul Harvest (try to harvest 5 souls for the +50% intelligence bonus). Your dogs will follow you into the pack and you will have a pretty good spread. Use sacrifice. If you get a good Soul Harvest, nothing in the blast radius should survive.
Step 2: With the Next of Kin and Final Gift runes, the explosion should have left some health globes and a zombie dog or 2 should have resurrected out of the rubble. Collect all of the health globes while your 2nd wave of dogs engages the surviving enemies. Since you are using Gruesome Feast, each health globe gives you +10% intelligence. If you got a Soul Harvest of 5 and you collect 5 globes, you will now have +100% intelligence (most likely you will have +70%–80% since you won't always get a good Soul Harvest or 5 globes). Detonate the 2nd wave of dogs that resurrected from the first blast.
Step 3: Pick up the health globes from the second detonation, and repeat Step 2 if any more dogs resurrected.
Step 4: Once you are out of dogs, use Grasp of the Dead on the survivors and start firebombing them. With the +100% intelligence bonus, you will do massive damage. Pick up any health globes left behind because the +10% intelligence bonus from Gruesome Feast only lasts 10 seconds.
Step 5: Kite any survivors with Grasp of the Dead and Firebomb. Hopefully your Gargantuan will help you here. Resurrect your dogs as soon as you can and repeat step 1.
With regard to gear, I build for (1) intelligence, (2) vitality, (3) increase health from globes, and (4) increase range on health globe pickup. With a high vitality and Gruesome Feast, health globes become a valuable commodity.
Finally, I like the extended duration on Soul Harvest in case you get a bad one. The cool down on Soul Harvest is 15, so if you only get 1 or 2 you can re-harvest after 15. But if you get a good one (4 or 5), it will last for a full 60 seconds (coincidentally, the cooldown of Summon Zombie Dog).
Like I said I am level 58 and I am in Act 3 Hell and this strategy still works very well. When I solo I use the Templar.