I finished the fourth chapter of the season with my witch doctor. She was powering along but now seems like she's flying. Lots of damage, reasonably safe, and the paragon levels are piling up so quickly my items and game difficulty settings can't keep up - 6 or more levels doing a set of 5 bounties, about the same for a greater rift. I went up 3 paragon levels just from the bonus xp talking to Orek after a rift. I've got a ruby socketed in my helmet (don't feel the need for diamond or amethyst) and I think that's making a big difference, next session I play I'm going to equip Leoric's Crown in the cube, run rifts for an hour and see what happens.