The pet bonuses are too small to be meaningful, to the point that even though it has +1 necro, having +all is worth more than the pet bonuses. If the pet elemental resistance was bumped up a bit, it might become useful to Ritualists since the Shaman side is not quite as skill-point thirsty as Occultist, and they need the pet elemental badly. (I’m talking 30%, I don’t know that I’d even bother with it at 25% unless there are other changes elsewhere that help enable Ritualists)
I used this in the Chaos variants of my Lost Souls and Ghol//Wraith builds. This item has some real uses, it’s fine.
As a side note. There are 3 legendary pet off-hands with +1 necro, and none with +1 to either Shaman or Occultist. That is a large part of why Cataclysm’s Eye is always used on pet builds.