1.: as said ^^ They should have more though, no race should be low on lore.
2.: Never said they shouldn't on others. Just saying that it should be more visable on Blood Elves as they are not used to brute force (melee). Of course this could be applied to other races, but some it might work other way then. For example Orcs, they might need to have a weaker looking model for the ones making a non melee? Orcs models already fit their brute and fierce way of living. Tauren's also, a noble and peaceful race, but with the muscle to crack skulls if the reason is there. Only ones I would allow to see a "buff" option for melee would be such as Sin'Dorei, Humans, trolls mostly. Night Elves for some reason I've been looking at, has an okay figure to fit a melee as well.
3.: There's supposed to be very few Sin'Dorei as well. Many followed Keal'thas and adventurer's then slaughtered them. Only some stayed back to tend their land and await hope. And a group went away because they are like some RP'ers (not bashing needed, but some bad RP'ers does this) they wont accept what has happened and they seek to just leave the area and find a different path than the main group and forget. Is that called arrogant? (not sure). And the whole of picking a Kaldorei to play a Quel'Dorei is just no.. You are not even close to be something alike it, too much difference (I know RP'ers do this though to atleast have a chance to act like one on Alliance). And rolling a Sin'Dorei on Horde to be a Quel'Dorei would leave you on enemy grounds.