Priests certainly should not be happy with hunters stacking on stamina so they live longer.
If the hunter is getting chewed on then there's something wrong happening and no amount of +stamina will make me happy about it
Feign Death + Traps + Pet + Kiting Ability = Hunter shouldn't be getting slapped around. Of course it's not necessarily always the hunters fault, could be a poor tank, or several other reasons. Point being though - stamina for PvP, not for PvE. I want my hunters to be crazy damage engines!
And as for leather.....pah. Although I'm not familiar with the specifics for hunter endgame itemisation there's no reason leather should be better than mail. It should be worse.