Judging by current things we’ve seen in manga:
SS - Luffy/Marco/Yamato/Zoro
S - Kid/Law/Sanji
A - Jinbe/Drake/Killer/Franky
B - Brook/Robin/Nami
C - Chopper/Usopp
What has Zoro done in this arc that's major?
The scar he did wasn't a majorninjury which weakened kaido like how GK weakened Doffy.
1. Luffy - the saviour of Udon and Wano
2. Momo - the most important person
Both are the Big Leaders!
3. Yamato - stalling Kaido for Luffy
4. Kid and Law - keeping Linlin busy
Preventing Yonko from rampaging the whole island
5.Sanji - Saving Momo from death then Chopper and co from Queen and Pero
6. Marco - halting the Plague progression and Stalling Calamities.
If Sanji didn't save Momo, the war is over!
If Yamato doesn't stall Kaido, everyone indeed the roof will be beaten or killed.
If Kidd and Law didn't fight Linlin, She'll continue continue chaos.