A bootleg version can never be better than the authentic one.
First, Sabo being introduced into the flashback was just random. And it was so convenient that he died in the flashback, had amnesia and appeared in Dressrosa. It's just so Oda could have an excuse to not explain why he wasn't in the story earlier because with Ace present in the story, this bland, boring, generic blond bootleg version has no place.
His only hopes as a character is to piggy back off Ace's legacy by pretending to be a "new version" of him, but developped in an inorganic way and forced into the reader's faces as if we should immediately like him. Other than being Luffy's long lost but still cool big brother, he has nothing interesting going on.
And Sabo using the Mera Mera no mi better?
Oh please! He just copied Ace's signature move like the uncreative bootleg version he is.
I sure hope Akainu fist him too.