One thing I like about the recent writing is how Oda is going out of his way to show that even though Imu recognizes them as Joyboy or Davy Jones, the characters themselves have no idea wtf he's talking about.
It’s not some hidden double personnality or reincarnation, Imu is just putting the blame on characters that died 800 years ago for ideologies that keeps on existing without them. He's really against progress that is all.
He wants his world to just stay in the past.