Hello, MtG thread! Unsurprisingly NeoGAF turns out to be the most fun place to talk about Magic online.
Very true, and that's the cool thing about the Tarkir idea. Rather than "the Asian plane" or "the Mongolian plane', it's much more accurately described as an Inner Asia or Eurasian Heartland plane, what remains of Asia when we cut off what we think of as the major civilizations: Greece/Rome, Sumer/Akkad, India, and China.
For Magic, they had conveyed the Silk Road's vibe of cultural and ethnic diversity remarkably well. Although one can argue Tarkir is still hamstrung by how one-dimensional Magic's depiction of the colors is, particularly black and red.
Specifically:
Abzan draws from Persia, seemingly with
Towers of Silence replaced by kin-trees.
Jeskai has Tibetan/Nepalese/Bhutanese architecture married to an Avatar-inspired kung fu theme.
Sultai is all about imagining the Khmer Empire and Angkor Wat as a Temple of Doom-style Orientalist fantasy, with emasculated men practicing necromancy and throwing their enemies into crocodile pits.
Mardu is the weakest. It has nowhere near the richness of real steppe cultures.
Temur is Siberian shamanism.