The only problem with this 5v2 turning into X vs 1, is that there's simply NO WAY people will get satisfied with whoever fights Big Mom.
despite the fact that I like her way more than Kaido, the lizardboy is the main villain right now. Big Mom is just an extra thrown there to not waste another arc with her.
Aside from Luffy, the other 4 have way more desire to fight Kaido, not Big Mom. So unless they send Big Mom away, and we have a completely different tag team against her, while the 5 remain there to fight Crydo, this split is most likely gonna feel like dog shit to whoever gets stuck fighting her right now.
Should just keep the 5v2, IMO.