Ok some alternative for the final battle against WG:
Luffy vs Imu (duh)
Sanji vs Ju Peter (Cook vs Guy who is in charge of food production)
Zoro vs Nusjuro (Swordsmen duh)
Law vs Mars (I have a feeling Mars had his hands in the destruction of Flevance; as Godhead of Enviroment he had probably interest in the Amber Lead)
Kid vs Saturn (Mechanic vs Scientist)
Koby vs Warcury (Honest Justice vs Godhead of "Justice")