In Blizzard's World of Warcraft Public Test Realm patch 2.3.0 notes, you may have noticed that there's mention of a new pet script which makes pets attack a target from behind thus avoiding any possible parries or blocks from the opponent.

Mania, a hunter on the Farstrider server, tested this and posted her findings on online site Mania's Arcadia. She discovered that when the pet is tanking, it doesn't try to attack from behind and keeps going toe to toe with the enemy.

However, when her hunter had more aggro than the pet, she found that it would attack the opponent from the side instead of the front. While this is good in theory, the pet would often spend a lot of time repositioning itself instead of attacking the enemy.

Judging from her findings and other accounts, this new pet script still needs some work. Hopefully, Blizzard fixes this up before patch 2.3.0 goes live in the actual servers.