The new POV
Well, in the beginning it seemed like it could be one among Sandor Clegane, Loras Tyrell and Melisandre. Then Martin stated that it would not be Sandor (http://www.westeros.org/Citadel/SSM/Month/2008/04/); it seems to me that he may be removed from the list, couldn't he?
Moreover, during a sign in Spain on July, 24 Martin said that the new character would not be any of the Tyrells.
Therefore, I don't think it's speculation if we put Melisandre as the new POV in ADwD.