Good question. Hopkins had Tarver, Wright, Daniels, Lipsey, John David Jackson, Holmes, Syd Vanderpool Mayweather had Pac, Guererro, Judah, Mitchell, Corley.
Not particularly susceptible, no. If you're asking did some talented southpaws ever touch him with left hands, well of course they did. Even the best defensive boxers in history got tagged with every punch in the book at some point in their careers. You could selectively edit together a highlight reel of Pep or Whitaker getting clobbered and posit the fallacious argument that "see, he was open to [insert punch]..."
