Some suggestions:
1) War rank should be like nw: war rank for each country and alliance war rank is summ of all war ranks.
2) Each attack (as option each attack not SS/PS) should add some for war rank. And it should be based on def str of country.
3) Also war rank may be based on attack result. And maybe some extra rank for kill.
4) To prevent late FS vs early FS, multiply rank for each attack on 1-turns_played/max_turns_for_reset