Nonsense. Brook is totally a badass.
Frankly, they didn't NEED to finish her off, because she's a fruit user, and they had cuffs. They just needed the ONE FUCKING PERSON present that could actually TOUCH the cuffs to not be a chickenshit for 10 SECONDS, and cuff a fucking unconscious person.
I liked that he said Zoro was considered the Vice Captain(1st Mate). I'd always felt that way, but nobody in series had ever said it before. He's always just described as the Strawhat's swordsman/warrior.