Naga
Ethereal
Neither
Neither make sense for a playable race, at all. If anything add Ogres as a playable race. Maybe for both Horde and Alliance? But to be honest I think instead of new races to play as (I think there is enough playable races to choose from) Blizzard should add like "sub-races". What I mean by that is like say you make an Orc, you can make your Orc look like the green Orcs or the brown Orcs. Or say you make a Dwarf, you can make him look like the normal Dwarves or the Wildhammer Dwarves with the tattoos on them. If not that then they should just update the models for the old races.
I don't think we need anymore races or even classes, I think we have enough.
"Wine was invented by the Romans... for orgies. And orgies are not too much fun if no-one wants to do it with you."
"What the heck you gonna do if you're on a picnic and have an ice cream and the ants crawl on the ice cream, what are you gonna do? You're gonna eat the ants because it's made out of protein."
For your health.
Cloudy with a chance of BOOOOOOOOOOOOONE STOOOOOOOOOOOOOOOOOOOOOORM!