I tend to think most people overrate CLs, but Maillot is the exception as a consistently unhittable guy out of the pen. His WHIP was under 1 (usually well under it) 10 times, and 0.86 for his career. He had 7 consecutive years of an ERA in the 1s (and 3 times flirted with it being under 1.00). This isn't small sample-size fluke seasons.