Shanks will probably have a clash with BB sometime in the near future however that fight will interrupted or end without a winner. Shanks is not endgame for BB, luffy is.
Who will Shanks fall to? Kidd. Why do you think Oda has designed them so similarly? Why hasn't Oda allowed them to have any direct dialogue? Why did Shanks mention South Blue when reading the info about Kidd?
Another hint. Does anyone want to guess who played a role in running those gangs that eventually killed Victoria? I'm willing to bet its Shanks.
Elbaf is the perfect setup for it. Luffy views Shanks as an Idol/Mentor/Hero. Kidd has been targeting Shanks even before he lost his arm. At the moment, Kidd has no idea about Luffy's relationship with Shanks. What will happen when Kidd learns about Luffy's relationship with Shanks/Dorry/Broggy?
And to top it off, the direct comparison to Joyboy from Oda. The only other supernova to receive a direct comparison to Joyboy.
And the vivre card gives it away...
Translated-
Yellow Text:
Alliance with the "Surgeon of Death" to defeat an Emperor!! Off to Elbaf for revenge against the "Red-Haired"!!