Some of yall need to understand what "villain" means. 😂 This is a manga/anime. Of course Heroes especially the strawhats will gain strength. Their willpower is enormous after all. Would be wrong if a villain killed a straw hat member especially one that already appeared once. It would only make sense for oda to showcase how strong the strawhats have gotten since that point. That doesnt mean villains cant be cool or strong. I love him as a character and as a villain. That's the point of being a good character. He stands up and tries again after all even if he can't beat them. It's way cooler than throwing away your plans or just run and hide like some others did. 😂 Without villains like that one piece would lose its whole coolness.
Probably not. He's too personal as a killer. He wouldn't want to exterminatus a planet from orbit. However, he would probably fit right in as an Eversor Assassin.