Many Kazakh or Uzbek persons could pass for Polish, while many others could pass for Korean. As far as I know, looking "Asian" or "European" has no cultural association. Why is this? Decades of Mongol rule? Russian immigration? Have these countries always had such diverse-looking populations?
Central Asia has always been a contact zone between Caucasoids and Mongoloids. Indo-Europeans have inhabited the area for a long time, Tajiks are Indo-European speakers and also predominantly Caucasian phenotypically. Today's western China was once inhabited by Tocharians, who were Indo-Europeans, belonged to a haplogroup charcteristic for Ukraine and could pass for westrn Europeans.
Subsequently the area was invaded by Mongoloid Turkic tribes, which intermixed with the previous populations and the result is the stew we have today. So it's not really a modern development.