Unless they are going to allow you to be on either faction with any race, which it's been hinting towards.
Then, even if you have a horde only race for it, you can choose to be alliance (but I'd assume they'd be fair and offer it to alliance race/s too).
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Rangers were trained in archery.
Hunters are more like people who live off the land, and with ferocious animal companions. While, I can't find the clip now, there was a dev at a blizzcon, while talking about big changes, said that, hunters were supposed to be a mix of melee and ranged, which is why originally you had moves like raptor strike. But, once people figured out, being at range was the best way to play, it made the melee moves pretty much useless.
While in current WoW, we don't really get that side of the hunter, at least we haven't in a while. That there should be a good enough reason. Hunters would typically want to live off the land. Rangers might want to go home and put their feet up at the end of the day. There will be similarities, sure, but I'd argue for other than using a bow and arrow - maybe even a gun - they don't REALLY have anything in common. I'd say, beastmaster and survival are probably the only *true* hunter specs out of the 3.