I have tried out a few combinations of skills and like others have stated, most everything works as long as the skill set is somewhat cohesive. Saying that, I worked up a fire/fetish doctor build that has been fun to play. The skill set explanation is as follows:
Fire Bats - Vampire Bats
Fire damage bats to go with the fire theme (take advantage of +fire damage equips) and no channeling cost.
Soul Harvest - Vengeful Spirit
Buff and nice damage for large groups of white monsters.
Big Bad Voodoo - Slam Dance
Don't need rain dance mana, so more damage it is for me and all the fetishes and doggies. Reduced cooldown by means of Starmetal Kukuri affix turns this into a almost-every-pack skill, depends on the DPS of you/the group. Also good for grouping.
Fetish Army - Legion of Daggers
More dagger wielding maniacs the better. Also, 3 more dudes to take advantage of affix on Starmetal Kukri (listed below)
Locust Swarm - Searing Locusts
This is mostly a flex-spot, but at the moment I'm running the swarm. Others reports nice synergy with swarm and area damage, so giving it a go. So far a good addition to the set, and fire damage.
Summon Zombie Dogs - Burning Dogs
Fire damage dog(s). I found a ring that summons a single more damaging, more HP packed dog in place of three. One dog not that effective, but can get up to five with Circle of Life passive. Good shields, 20% damage/second as fire.
Spend a lot of time channeling bats for free, so more Fetish army to proc Starmetal Kukri to cast BBV and Fetish Army more. Good support damage and things to get between baddies and me.
Circle of Life
Used to get up to 5 burninating dogs.
Pierce the Veil
Kind of a free passive, but there are relatively no mana issues so mana regen passives are lackluster. There are few mana spending skills so the 30% doesn't eat away as much. Have limited testing with this + spendy spell of locusts but so far mana hasn't been a problem.
Notable Legendary affixes that I currently have to assist the build
Reduce the cooldown of your Big Bad Voodoo and Fetish Army by 1 second each time your fetishes deal damage.
The Tall Man's Finger
Zombie Dogs instead summons a single gargantuan dog with more damage and health than all other dogs combined.
I'd really be interested in getting new full Zuni to see how many fetishes I can have stick around.
My gear from copied char is about 100k DPS, handles MP8 decently well in terms of survivability with life leech Skorn CoB build.
Anyone else having success with a fire- and/or pet-based builds?
Edit: Spirit Walk - Umbral Shock instead of Locusts may be good for added survivability + fire damage. See this possible as meet a pack, drop BBV + Fetish, cast bats for a while, spirit walk out when needed to avoid death + deal fire damage. Should get a nice grouping for most enemies to get hit from explosion.