I get that there are people whose idea of fantasy is a world where there are a plethora of races to play (or fight). Maybe part of that comes from D&D, maybe it's influenced by the crop of MMORPG's where race is primarily a simple choice of aesthetics, I'm not really sure. Either way I think the main driving desire behind that is the notion that more races = diversity.
This is understandable. I don't think that races are the only way to get that sort of diversity, mind you... and I would say that Dragon Age is specifically focusing more on the experience that the player will have in this world. Rather than offer a whole bunch of cosmetic choices, we offer a smaller number of choices but try to make them much deeper -- your choice of race and class affect much more than your appearance, they dictate your entire introduction into the game and the world.
I suppose there are some who will still be put out even so, lacking the option to play their favorite sort of gnome or ogre or what have you... and that really can't be helped. Every decision we make on what the Dragon Age world is means there is one more thing it isn't. We're fine with that. We're not trying to please everyone, we're trying to make one thing and make it well enough that perhaps some of these people come to love it for what it is rather than dislike it for what it isn't.