Gin was a prodigy too. While almost no one knew about the full extent of his power, I don't think he'd be anywhere close Yamamoto.
By the way, what happened with some of the stuff that Kubo mentioned in his interview before the last arc, e.g. Matsumoto playing a key role (or something along the lines) in the arc? Have I missed something, or is it just Kubo being Kubo, or editors shitting on his plans?