I was going to defend Karloff's looks, but teenybuffalo more than covered that!

I don't think Karloff isn't interesting to look at. Rutger Hauer's Roy fits a very specific physical ideal which for me informs the character in a way I feel shouldn't have been impossible to approximate in the 1940's, especially with the tidal wave of German emigrés in Hollywood (I know Hauer was Dutch, I also know how Americans are about European accents), except that I'm having trouble finding anyone!

Then it occurred to me that the world's most perfect casting would be Max von Sydow, except that Sydow would be a tad too young in the late 1940s...

Seriously! Everyone who occurred to me for Roy was either Conrad Veidt or a decade too late.