The following bugs are pretty huge and have been around on the private servers since they've been a thing. This puts hunter class at pretty considerable disadvantage, and frankly its getting harder for me every day to suppress the feeling of logging off and deleting my hunter. Here is the list
Pet movement - most crucial bug. Even if you have the 30% speed talent and use aspect of the pack on top of that, anything that you might try to kite and is moving - pet will lag behind it and do no damage even though its faster than it. Crucial bug. On retail even without 30% talent and without aspect of the pack the pet would with no trouble dps on a moving target. Here because of this bug, soloing certain elites is simply impossible. Very very generic bug.
Mend pet - if the pet is at full health, mend pet has absolutely no effect (there are no ticks from it). Not a very crucial bug but whenever you spec into improved mend pet, well, if a mage freezes/polies your pet or you're trying to dispel some slow from a mob, you will not be able to.
Improved Mend pet - Has 50% chance of dispelling only on the first tick, but not on every single tick as supposed to. VERY generic bug.
Pet resurrection - if your pet is dead and then it disappears, you have to call him first instead and then res him. Not a major thing, but you guys supposedly had attention to details and this is a pretty generic bug. If your pet is dead and has disappeared you shouldnt be able to call but only res it, and thats how the pet appears.
Pet resistances on applied debuffs - dont seem to work on applied debuffs like poisions/frost nova/root etc.