Don't think Luffy will lose again Oda has made it very clear Kaido has been superior Luffy needed tons of help so far i don't see any purpose of making him lose again Kaido has been through a lot. He is at a stage where Luffy should be taking him on and actually win with whatever PU Oda will give him.
This final fight against Kaido will have two stages
1. Is now
2.when only Luffy & Kaido remain