Why are most of the people so salty about Sanji taking on King? If he cannot take him down, hurray for you. If he can and if Zoro plays major role in taking down Kaido/Big Mom, Zoro will still be stronger than Sanji by logic. Yonko’s are several times stronger than their first commanders and Zoro taking Kaido/BM down with 4/5 SNs will not change the fact that he accomplished a great feat.
In the end, original strength dynamics will be preserved and both of them would accomplish great things.
After all, don’t you all want SHs to be a strong crew? It is not logical to classify the crew as Luffy, Zoro and remaining trash in that case. You should be happy that everyone would get stronger like they did in EL