Before 2.4, growl, which is a high aggro spell used by hunter's pet to tank for the hunter, scaled, using pet AP, which is in itself scaled using the hunter's AP. Based on personal experience as a hunter, this was fine, except that boars have the spell boar's charge increased the AP of the next attack, which pre-2.4 was growl, making boars quite imba in solo play.

Blizz changed this in 2.4, first by nerfing growl not casting immediately after charge, and another by somehow nerfing growl itself (I don't know how, but again, on personal experience, my hunter's pet loses aggro easier after 2.4, no other changes done).

Apparently to compensate, growl will now use the hunter's AP as a modifier, which is definitely higher than pet AP, so in theory growl will be improved or return to pre-2.4 state in it's power.

According to Mania, this is not the case, or there is inconclusive evidence that growl has been affected.

As a hunter, it's quite a concern, but I guess I just adapted to the condition. I use FD more often in solo play now.