Opus has always been a hero of mine and I too will go with Bill D. on this one.
But on the other hand, maybe I should name Marcel Marceau as the worst. Why? Because he came along and as a pretty proficient performer popularized the (I hesitate to use this) artform. Before that, only a few simpleminded twits actually gave a shit. Then along comes MM and all of a sudden we're up to our necks in mimes. Most of these had no talent or even worse! We were inundated with gyrating assholes flailing around as if we're supposed to know what they're doing. Not only did we NOT know, many of us didn't give a bad fuck from a whore with the clap what it was they were doing.
Most people aren't aware that there are 5 classes of mime: Dumbfuck, Jackoff, Horseshit, Limpdick, and Fuzznuts. None are any good.