As title says, although the fight between Yonko vs Worstgen is starting in a 2 vs 5 right now, i think that Luffy will ultimately end up fighting Kaido in a one on one. To illustrate this, i'd take the example of dressrosa which started in a group battle, but Luffy ending up fighting Doffy in a one-on-one
Now let's talk about the reasons:
1- First of all, before the arc even started, Oda was already hyping up Luffy as a future 5th emperor of the seas
This suggest imo that Luffy should come out of the Wano arc as a powerhouse recognized on a similar threat level to that of an emperor
2- Before the arc started once again, Shanks was already suggesting that the time to meet Luffy was close, and that was before Luffy's udon training that made him much stronger
And while we're still in the Wano arc, Oda implied that Shanks is about to move
Which further suggest the time for their meeting is coming closer, a meeting that Shanks only wanted to happen when Luffy would be recognized as a
great pirate(yonko)
This could once again only happen if Luffy comes out of the arc recognized as a yonko level threat
3- In the One Piece newspaper vol2 translated by Sandman, Oda pointed out that when Kaido was introduced(shortly after Doflamingo's defeat), he didn't think Luffy could defeat such a strong character
yet.
The
yet is important here, because it means Oda was already thinking back then about ways for Luffy to defeat him, and since then, Luffy learned new tricks like future sight from his battle with Katakuri, allowing him to predict things in advance, and level3 hardening on his way to learn level2, allowing him to bypass Kaido's durability even with a gear3 attack and thus his way not to make Kaido's defeat appear just because Luffy's punch is so strong. By giving him future sight, and level 3 hardening, it granted to Luffy new tricks that Oda thought in his mind could make Kaido's defeat satisfying for the reader
4- In his introduction, Kaido's main theme was resolving around the fact that you always have to bet on him in a 1 on 1 fight
And we know Oda always love to make Luffy destroy legendary myths like he did with Katakuri's track-record
This is why imo, Oda would at one point make Luffy fight Kaido in a 1 on 1, beat him and destroy this myth around always betting on Kaido in a 1 on 1
5- In the latest chapter, Oda decided for Luffy to be the one to carry the burden of Oden and his retainers in order to save Wano infront of the yonko
Which imo will lead to Luffy being recognized as the savior of Wano
Thanks for reading