As of 4.0, everyone has 100% accuracy when attacking a mob of equal level from the front. Flank and rear still provide accuracy bonuses, but since you have 100% accuracy from the front when attacking a mob of equal level, these positional accuracy bonuses are only relevant when (a) leveling and hunt/quest mobs are a higher level, (b) you are debuffed with blindness or some other accuracy down, (c) your target is buffed with evasion up. B and C are quite rare.