Dorian Yates isn't even close. Neither is Mark Dugdale or Ronnie in 2002. Claude Groulx and Ahmad Haider win the "smallest arms" awards for male competitors in the last two decades. Proportionately, Art Atwood might take them all.
Before that, poor Chris Dickerson took "top" honors. (How he ever won an Olympia's beyond me. I hear he's a sweet man, but I'm sorry: slowly moving one's arms about in circles doesn't make for great posing, either. You want good posing? See Shawn Ray in 1994.)
I am sorry but if you go back and look at photos from the 1980 Olympia, you will see that Chris actually has some damn impressive tris and also incredible back detail, along with having some of the best calves ever!!!! His bis were subpar but his tris, calves and back detail were all out of this world. IMHO