To me, this wouldn't change anything about Kaido's level at all. Kaido has proved to me his title is legit and he is truly the strongest creature in the world. If Kaido takes this giant punch and is still up and moving after tanking it, that'll be legendary. I think this build-up between Luffy and Kaido clashing in Ch. 1047-1048 might be set up for the end of their fight though. Hey, we can have another six or ten chapters of this fight, and I wouldn't mind that at all.
For Oda to start with Luffy's first attack (that actually did damage to Kaido) against Kaido in Chapter 1000 and ending it with Luffy's final attack against Kaido exactly 50 chapters later in Chapter 1050 sounds like something Oda could do.
The question of whether Carrot or Yamato will join is one of the most entertaining discussions here. It won't be long before we know who it will be. One of the two sides will need a good explanation afterwards. Maybe both will join, but I doubt it.