The Witch Doctor is a class that is difficult to train a secondary school for. For mine, I trained Light Armor (for more clothing choices), Rouse, plus up to the group heal. I also trained Rough (more damage).
KI will be adding more options to the weapons, such as Staffy/Slashy, Staffy/Stabby, etc. So, if you can't figure out what to spend your training points on, save them as the game will continue to update with more things that a Witch Doctor may need in the future.