Alliance hunter get blessing of wisdom, blessing of kings AND judgement of wisdom, which means they get a significantly superior mana regeneration compared to horde hunters. Serpent sting will see quite a bit of use in raids for alliance hunters, but not so much for horde hunters who will go oom way faster now in comparison.
It’s not so much about the 40 - 50 dps gain that serpent sting will bring than the fact that you got a less interesting gameplay by not being able to use it at all as horde in raids that makes it sad…
Sucks doesn’t it?