That's what I was arguing—my interlocutor seemed to think they were just groups of Aqir which took on new names with their new cultures, with their varying physiology only being the result of the preexisting dimorphism of the race. Your post puts what I was saying more eloquently, though.
The reason I was citing using "Aqir" to refer to a specific specimen was because I think that implicitly suggests what you were saying—if the Aqir were a vast classification, as opposed to a distinct predecessor race, it would be odd for Blizzard to label a particular breed with what my interlocutor stated was a blanket term for all of them.