So with the Wano Arc Act 1 coming to an end, I think Oda set it up nicely, with his whole "thinking of an Idea to Take down Kaido". Luffy is an impatient person, he attacks first and asks questions later, in some cases its a good trait to have I like that about him, but as a Captain of a Ship and also going against a Yonko, you need to follow the laid out plan, but two things to take away from him diving head first, (1) The power level difference between Luffy and Kaido and (2) Luffy has gained respect and maybe even some allies by showing his courage and Conquerors Haki. The re-introduction of Kid gave me a flash back of when Kid, Law and Luffy fought against the Marines on Sabaody Archipelago, where they were also competing against each other, in this could pose a Solution to taking Kaido out, 3 Captain's with different abilities constantly attacking could work. Law learning about the Seastone Nails, Law will acquire more nails and implant them inside Kaido's body, he doesn't need to pierce the body due to his ability, this will leave Kaido weak and unable to defend himself, since his skin is tough there won't be a way to get it out. Couple that with Luffy's crew and other allies taking care of the Beast Pirates and Orochi's Samurai, they can have an uninterrupted fight with Kaido, also Kaido's allies believe him unbeatable so they won't join in anyway. This is in theory how I believe Kaido will be defeated, Oda left some hints here and there but overall I think this is how it will lead up to Luffy giving the final blow.