Bearing in mind that the playable races in this game are GOOD, the next playable race should follow this model. How about 4 inch tall brownies? Of course, their riding critters would have to be proportionate to their size. Like, maybe, grasshoppers. Or birds. Or oversized garden snails. Wait, I know. Rabbits. Four inch tall brownies riding pink nosed rabbits. And wielding oversized sewing needles.
I love the idea, really. Brings the movie Willow to mind:p. Can just hear it now tho, some human running around, *squish*, oop, stepped on a brownie

. Still got my vote for this tho.
With the idea of balance in mind, would love to see minotaur or even orc race added. Though this is what I now play instead of WoW, I honestly dont believe it would be too similar or even considered borrowing or stealing the idea. Orcs are just too inbred into the good vs. evil fantasy themes, and would really add the balance some may be seeking for in RoM.
Just my opinion, could be wrong