While some might see the Spiritborn as Diablo 4's replacement for the Witch Doctor, the two classes could actually be the perfect complement to each other. Many players view the Spiritborn as a combination of Diablo 4's Druid and Diablo 3's Monk, and while this argument is valid, it also shows where the Witch Doctor could fit into the class line-up. A core part of the Witch Doctor's kit is its ability to summon zombies and vermin, making it a close cousin of the Necromancer, but there is still a lot of room to make Diablo 4's version of the Witch Doctor unique.
Aside from summoning minions, Witch Doctors can also wield ceremonial daggers as their primary weapons, making them similar to the Rogue in terms of basic weapon attacks. A Diablo 4 Witch Doctor could combine a number of elements from two popular classes in the Necromancer and the Rogue, leaning into the agility of the Rogue with the Crowd Control support offered by minions to create a brand-new play style. Although the ending of Vessel of Hatred leaves a Paladin or Crusader-type class the likely next option, Season 7's Witchcraft mechanic should open the door for the Witch Doctor's return as well.