Just to give you an idea how fun this spirit build must be; here's what a standard rotation would look like:
1- A big mob is coming your way. Get as close as possible, Mass Confuse their A$$ and Harvest their Soul. Now let's say half of the mob is on your side for 12 seconds.
2- Spirit Walk out of danger to let your physical body act as a punching bag for the other half to fight. Meanwhile, the mobs on your side aggro them.
3- At a safe distance, Cast 1-2 Haunt and spray SpiritBarrage.
4- As soon as you're in trouble, cast Horrify!
5- Repeat step 3.
6- As soon as you're in trouble again, cast Soul Harvest for the slow and kite.
7- If it's not over yet, your Spirit Walk punching bag is up and should at least have one Zombie Dog spawned for distraction...gg.
As you can tell, a pure spirit build is all about field control. IMO, it's where the WD shines and will make this class so fun to play. Any input to make this build / rotation better would be appreciated.