Brienne is a tough one, because the idea I kept getting from Martin was that she would have to be someone with a mannish build (I guess they could alter her build with padding and other makeup effects) who could be mistaken as a man when seen from affar.
So she doesn't exactly have to be "homely" but more mannish, and I believe Martin specifically describes her as small breasted, so someone on the athletic side could be good.
I like the idea of Katie Sackhoff because she could easily be madeup more manly and tough (as in early BSG episodes). But I've also seen her with her hair grown out and makeup on and she looks really good, so she can make that transition. And she can do the action.
However, I would like to see an actress "discovered" for this role. This role could be a real career maker for an actress who doesn't have the perfect look that casting directors usually favor.
A name I haven't seen put forward yet is "Mellie" from "Dollhouse" Miracle Laurie. She may be a little too busty for Brienne! But she's 5'9" and seems to have the acting chops for this type of role.
http://www.imdb.com/name/nm2829954/
http://www.fox.com/d...ers/#bio:mellie
These are pub photos, which means they are approved by Miracle and her management people, so she's looking her best, but if you watch the show, they play up her "average" looks.
But imagine being a budding young actress, getting a call to audition for the hot new series on HBO, and you find out they want you to play Brienne! What a shot to your ego. Kind of like when Margaret Hamilton found out they wanted her to play the Wicked Witch in Wizard of Oz!