So, Elbaf.
Plot #1: The World Government invades Elbaf as Luffy is there.
Plot #2: The relationship between Shanks and Luffy finally deteriorates thanks to Bartolomeo and Hajrudin's actions, and Luffy being Nika and all.
Plot #3: The arc is largely insular, with some sort of internal conflict. Maybe a issue of succession for the King?