-Shanks likely only arived there to stop the WG bullshitery, dosent change the fact that he did sent Kaido packing back with his tail between his legs before going to marineford. He might even intendeed to woop the floor with Kaido if Luffy failed too
-World strongest person>>>>>>>>>>>>>>>>>>>World's strongest monster, primebeard gotthe tittle of the strongest man in the world, while Kaido already had the WSC tittle. Plus, no way Oda would put Luffy in a 1v1 with the strongest pirate since the last saga is starting now, meaning there will be plenty of 1v1's for Luffy against other pirates, and it wouldnt make sense in a shonnen manga for Luffy to be stronger than them already unless G5 was temporary, wich is likely not.