Personally, although I love XIII, I don't think they should release an updated version. I'd rather see them utilize their resources to create a new KoF with what we want(characters, stages, intros, more moves, etc.).
KoF XIV should do what 98UM and 2002UM did. Add ALL the characters and bosses from the last saga, use one of the gameplay engines used(in this case it would be XIII's, I don't see 2003's/XI's or XII's returning.), add Rugal, Goenitz, and the New Face Team, and viola! You got yourself one hell of a dream match!