Yeah I really don’t. Not odas style to write a multi prong war. Makes much more sense to write a series of fights that lead to an inevitable end.
The issue is assuming there are any more relegated "kingdom" type arcs after Elbaf. Teach isnt a tyrannical ruler of an island needing to be saved. Shanks doesnt even have a canonical home base at this time. Akainu is in charge of a base which he may not even need to stay positioned at in the end.
I think if Oda is implying the scale of the final conflict is much larger than Marineford, then its clear it needs to involve more than 1 Yonko and the Marines in the least.
But lets even assume its not and its just a continuous bout of fights at separate islands:
- We still have Elbaf, Lodestar and Laugh Tale in the least, but we should also be including Law's original destination
- If you want to "compare" those to the 4 "known" characters who are viable threats to Luffy, then you have Blackbeard, Shanks, Akainu and Imu. Obviously it may be more or less, idk
- This is also not including the "potential" for things after Laugh Tale (i.e. Marijoa or God Valley, etc).
So I dont think the issue is necessarily the number of people standing in Luffy's way. Geographically, the story already can support 3-4 more antagonists with minimal issues.
But this is why I doubt the same rudimentary approach to arc villains post Elbaf, because 4 is a lot in isolation from each other. We have it in Egghead potentially. And Elbaf may or may not be its own thing or with one of those remaining 4 characters, but after this theres no indication that we "need" to have a basic structure with islands moving to the end.