Old thread, but an interesting topic. One big reason nations like Armenia and Georgia are so good at Judo is that it's not all that different in many ways from their indigenous wrestling styles which are contested wearing jackets and pants. When leg grabs were still legal especially you used to see a lot of indigenous influence in their styles, much like you still do with Mongolian Judoka. And of course, there's just a strong culture of grappling in all the former Soviet republics that goes back many centuries. If everyone does it, the best ones will be pretty damned good.