Oda has to walk a pretty fine line with Hatchi, portraying him as a decent guy who wants to run an octopus fritter shop while also acknowledging that he did some pretty heinous things in the past. Oda generally does a good job of presenting a handful of his henchmen characters as just people who for various reasons got caught up in circumstances that led them down a bad path. Not everyone needs to be a cackling maniac, but Oda maintains that balance by not shying away from the bad that they've done. As the henchman who's gotten the most development Hatchi is the most successful version of this in the series, and Oda uses Hatchi's development to show how Nami's grown as well.