Any ideas on the hero from West Blue? Is it even important enough to try and guess?
My best guess, and this is just me spit-balling without much to go on, is that it's going to turn out to be Joyboy's Sword Guy.
Chances are, Joyboy had a Sword Guy. Oda loves his parallels and patterns. And almost every crew has some sort of Sword Guy. So, I feel like that fits.
The shrine is in a state of disrepair. That seems to indicate that it's a old shrine. This being a shrine from the Void Century would make some amount of sense.
It probably can't be Ryuma. For one thing, Ryuma's body was on Thriller Bark. But, also, Ryuma probably can't be Joyboy's Sword Guy, just because Ryuma likely isn't old enough. He probably lived sometime after the Void Century. Sometime around 400 years ago, not the full 800 when the Void Century took place.
So, at this point, I think Oda's going to try to flesh out Joyboy's crew a little bit. Plant a few seeds so he doesn't have to introduce everyone all at once, when we do get that inevitable Void Century flashback. It makes sense to introduce one of Joyboy's "wings" a little early. At least to me. Otherwise, I have no idea who it could be.