After extensively playing all the classes, WD's SH is actually underpowered. I have been playing WD mainly and have come to a realization that the class, overall, is underpowered.
Part of this is the pets, I don't know much outside of numbers and theory of the Garganutuan, but the Zdogs are only going to become more and more underpowered as levels and difficulty increase.
Soul Harvest is "a little above average" - at early levels if you take into account travel time to get to a pack of 5, the possibility it won't always be 5 stacks, and the vulnerability and "not DPS'ing while moving" that SH requires.
I leveled up both a Monk and DH after the WD on the last wipe. The Monk seemed to hit harder than I remembered compared to the WD, I had about the same level gear I had the last time I leveled up a monk, except I equipped him with a 2 hander (2hander monk is the way to go IMO).
DH was no contest. Just spamming their first primary skill does more damage than any SH/ability finess the WD needs. That's just one skill... and it wasn't even a revenge dump, it was a revenge generator.
WD has little/no mobility (sprint, leap, dash, teleport, whatever).
As a WD, once you are in the thick of it, you are in the thick of it. And if you mis-manage your mana use without an "Oh-shi-" button/ability, it will be certain death, ESPECIALLY at higher difficulties.
DH as a comparison has two resource pools, one of which you can replenish as quickly as you use it, and the other gives you all sorts of simultaneous survivability utilities that don't infringe on your DPS.
Sould Harvest is being touted because people are seeing it through level 13 normal capped gameplay. It is really difficult to estimate how it will perform at end-game, but taking SH out of the picture for a second, the WD is a bit of a weak link as-is.
Pets seem under-powered, even as meat shields, WD's don't have much in the way of real survivability from mob trains, Their resource architecture means they have nowhere to go but down in most cases, and their damage, realistically, is sub-par if you factor in the necessary micro-managing SH needs.
Ask yourself this.
If WD didn't have SH, would it be as good of a class? -That's why it is an underpowered class, one skill makes it go from average, to below average.
The exception to this might be a specialized WD who intimately knows their weaknesses and designs a playstyle outside of the scope of SH, (even if they use it as a skill).
In my opinion, there will be 2 kinds of WD's.
Heavy dot/damage/Buff doctors meant for 4 mans. They target larger threats with stacked dots, manage their mana and damage through passives, and rely on 3 others as cc to buy them time to get the damage out. They will be designed around the concept of consistent damage.
Heavy pet survivability WD's, they take as many AI pets as possible and max out the pets, and their own survivability through poisons etc. They won't be primary damage dealers, but they will be PVM CC kings,
SH doesn't really fit into either of those two roles, ranged/dot with no pets to CC, or Pet focused with no damage focus because pets can't survive without the passives.
I was so sure for the last 2 weeks that I was going to roll WD as my first, but having given the other classes a second/3rd try with a truly open mind revealed to me the WD weaknesses.