Oda gave Luffy ruyo as a power up but he still didn't master it completely yet, and so he has still can improve it greatly and is gonna be very important against BB and the next opponents.
as we saw in the last anime episode it seemed that Luffy didn't use ruyo in combination with G4, but even he stated that he will use it in is last attack against Kaido, to avoid melting his hands, which means he didn't use it always against Kaido.
against BB his DF might turn very useless after all so he will have to rely on his haki powers.
as we saw in the last anime episode it seemed that Luffy didn't use ruyo in combination with G4, but even he stated that he will use it in is last attack against Kaido, to avoid melting his hands, which means he didn't use it always against Kaido.
against BB his DF might turn very useless after all so he will have to rely on his haki powers.