I genuinely think this would be one of the most retarded ideas Oda could pull off.
That's even worse than Scrubbards. Scrubbards are the side characters of the week. But de facto replacing Zoro and Sanji with Law and Kid to fight Admirals would be genuinely replacing your main cast with glorified side characters.
Not sure if you really believe that or you're just trolling.
The more it is less strawhat centric unlike team 7 was in Naruto and hog the spotlight of everyone else, the better a story would be. I don't care about who fights the admirals nor about who is stronger between Zoro and Sanji, but if Marineford and Wano did one thing right, it is not letting the Strawhats ( Team 7 or Konoha ) hog all the spotlights and defeats. The Akatsuki was defeated almost only by the leaf ( bad world building ) do you want that in One Piece just for a favourite character to go up the powerscale ?
But Katakuri never physically matched Bound Man. At best he deflected his attacks. Now imagine the same Bound Man being ONE SHOT by base Kaido. People questioned top tier powers after rooftop but Greenbull demonstrated yet again what it truly means to be a top tier.
Katakuri said they - him included - cannot stop TANTRUM Big Mom. I believe his words.