The worst VIZ translation imo was way before Stephen Paul joined.
On the first chapter of One Piece, shanks offers luffy orange juice to prove him a kid. Whomever translator it is, thought that orange juice isn't baby-ish enough and changed to milk! But as we've seen in WCI, Oda doesn't think milk is only for little children, as it regenerated Luffy's teeth and Brook's skull.
The second worst is "Reverie" (which was also probably introduced before Stephen Paul, but why do they still cling to it?). Even if the translator at the time couldn't tell it was Levely (Oda probably meant that all kings are on the same level), why choose a word for daydream to describe a meeting of kings? It was simply stupid.