Would be pretty selfish of hunters to demand a fourth spec when Demon Hunters only have two. I get your point about the ranged survival spec already being done so it would be easy to implement, but it would still be another spec requiring balancing in the future which takes time. This was also why Blizzard for example scrapped the warrior gladiator spec. I don't think Blizzard will give one class four dps specs. Would be cool though, but maybe a bit unfair. Just a point.