I don´t think he would ever want to be a captain, but I don´t think it would make any big difference to him if he was killing dissidents to some pirate ruled country, as opposed to dissidents to the world government proper. He just likes to kill,so you do have a point.
Rob Lucci was taking orders from a bum like Spandam with a smile on his face. Has no goal of his own. And his entire toolkit is the mastery of assassin techniques. To turn Lucci into a pirate is to create an entirely different character. He wouldn't even be Rob Lucci at that point.
I guess we saw WsW and he was a complete bum compared to Lucci. That's what happens at best if Lucci decided to follow Kaidou. It's actually a what if scenario of a Lucci who didn't make it as a CP agent. But again WsW didn't start as a pirate... he's just a CP agent who failed.



