If Oda didnt hold back, Kaidou will have killed all scabbards, all Minks, Zoro, Kidd, Killer, Heart Pirate Crews, Kidd Pirate Crews, Nami, Robin, Chopper, since rooftop, do you really want that kind of thing happening? I mean i know i do since i want Law for next nakama and Luffy will be too depressed since his crews are dead but if Oda didnt hold Kaidou back that would be what kind of happened.