Witch doctor companions in my opinion are the least useful low health, low accuracy, low dodge, low range, and low defense. It would be nice if there was al least one really good witch doctorpa companion with good health accuracy and range. I like the companions like mormo and serpent augur but they're just not that usful after all they're powers are gone. Maybe the new companion could be a human apprentice with maybe a little more accuracy if not the same as a privateer or Buccaneer companion about the same range and health as louis le bisque. Then they could give him or her powers like mojo storm, mourn song, and mybe another AOE like davy jones reach and then a buff which could be either raven's cry,crows song, big or great juju,or surpise me with a call to arms. I hope to see this companion along side my pirate

Witchdoctor (Dr.) companions will probably always be a little "squishy". Melee combat to them is as mysterious as Hoodoo is to a buccaneer. And metal armor seems to interfere with their mystic powers a bit. But, if you protect them with some magic or bodyguards, they can be powerful attackers for the duration of a battle.
The new shark Dr., Carcarious Grimtooth is the most accurate Dr. companion in the game right now because he can do Improved Mojo Blast and has Pirate 3 talent. Pirate talent is active all the time in PvP and only in enemy territory in PvE, but it gives him +50% Accuracy and +25% Damage. Improved Mojo Blast 1, 2, and 3 are Area of Effect (AoE) attacks, and target dodge does not protect the target from AoE attacks. So put a Valor's Shield/Fortress/Armor on him and run him down into enemy territory early in a fight and your Dr.'s shark will hold his own in the fight. If you have cross-trained Pirate talent with practice points, it may be worth your while to teleport next to him and do extra damage yourself.

WD companions are very different than Buccaneers or Swashbucklers ( yes, I'm stating the obvious ). Therefore don't train them like either of these. Boost their ranks in will and spooky, max these out. Throw in some points in accuracy and if you have any points left - dodge is very useful. I have trained all my WD companions this way and I'm very pleased with the results.
From the Crown Shop, I have bought Eep-Opp-Ork-AhAh and the Inoshishi Necromancer, these two are very useful companions to have.