Zoro and Sanji will save Robin from CP-0 watch
This is a super later reply because I have been busy.
1. Aren't Zoro and Sanji on opposite sides of Onigashima? If Oda wants them to meet up and defend Robin, then he will make it happen.
2. I personally prefer it if just Sanji is the leader of protecting Robin from CP-0. I want Sanji to lead Brook, Jinbei, and Franky as they fight CP-0 Didn't he tell Kuma that he would be the most dangerous threat to the marines and/or world government? I would like to see CP-0 have to handle this recently upgraded Sanji so to speak.
3. Sanji fighting CP-0 could lead to more Mr. Prince moments. Sanji's fights are different from Zoro's because he has the freedom to sneak attack his opponents. Zoro's fights follow the bushido code. Zoro loves to fight, and he looks at fights as a matter of strength and willpower. Zoro's philosophy is face your opponent head on. If you die, then so be it. It just means your opponent was stronger. Sanji doesn't love fighting. He fights because he wants to protect. If he has to sneak around and go behind the scenes to save Robin and defeat CP-0, then he will because Robin's safety takes first priority.
3. Just because Zoro and Sanji are Luffy's wings doesn't mean they have to do the same exact thing. Zoro could fight CP-0. On the other hand, he could also meet up with Hyori and help her defeat Orochi. Another possibility is meeting up with Yamato.
4. I also want Zoro to fight Kaido with Luffy. The captain and his right hand man fighting the strongest creature together would make me so happy.