Pets are simply not as survivable as player characters in Diablo 3. The amount of damage that they cause is negligible especially since they tend to die real quick when hit by boss monsters, especially in higher difficulty settings like Torment III and above.
According to Blizzard, this isn’t intentional, as philosophically, pets are supposed to be roughly as survivable as the player character themselves and relied upon in battle. Blizzard’s posted their philosophy of how they think pets should perform.
- Pets should scale with your survivability stats. They currently scale with most of your stats but not all of them. This is being worked on.
- Pets should derive their Toughness from yours, and if you skip out on it, your pets’ survivability should be noticeably lower as a result. On the flip side, they should be noticeably tougher if you’ve increased your own Toughness. You shouldn’t skimp on Toughness just because you have pets.
- We don’t want pets to be invulnerable tanks. In the live environment pets are too squishy, but even after our review is done in a future patch, if your pets are still dying a lot, we want you to be looking to increase your Toughness, which will consequently increase your pets' survivability.
With that in mind, Blizzard is setting it up some buffs for pets so that pets will take reduced damage based on how avoidable the monster attack normally is for a player. Instead of giving pets the AI to run away from damaging attacks, which would in turn cause them to produce less DPS, here’s how Pets will handle damage from enemies:
- Full damage to pets – Basic melee/weak projectile attacks, not expected to be always avoided by a player.
- Reduced damage to pets – Special attacks such as fireballs, which typically deal more damage than a basic attack, are pretty bright and visible, and can sometimes be avoided by the player. Good example are Perdition’s volley attack or Agnidox’s fireballs.
- Drastically reduced damage to pets – Persistent AoEs for which the player is intended to move out of quickly or highly-telegraphed attacks for which the player is intended to avoid altogether. Examples are Thunderstorm monster affix, Mallet Lord’s arm attack, or Morlu meteors.
Blizzard says this will all be addressed in a future patch for the game, which currently sits at version 2.1.0.