That's an awesome mod!
My suggestions on improving the map of China (more or less in order of importance):
1.
Original: ca. 700 AD
Current: 大約在公元七百
Should be "約公元七百", "約公元七百年" or "公元七百年左右". I suggest using the last one. "大約在" is colloquial and inappropriate, and it's a bit unusual to say "公元七百" without adding "年" (year).
Alternately you may also use "約700", which would be succint in an academic way.
2.
Original: Tibetan Empire
Current: 西藏帝國
Should be "吐蕃帝國", since 吐蕃 was an ancient Chinese name for Tibet, and is used to refer to Tibetan Empire in the time of Tang dynasty. The word "西藏" didn't exist back then.
3.
Original: Himalaya Mts. / Althay Mts.
Current: 喜馬拉雅山 / 阿爾泰山
Should be "喜馬拉雅山脈" / "阿爾泰山脈".
4.
In general:
You are now using very large font sizes in order to preserve the original shapes of the text, and the result doesn't look very good. That's not the right way to do it.
The correct way of lettering on a print Chinese map (sorry I can't find any example now) is the same as print Western maps: keeping an equal distance between each character in the same name.
This way, you can make the font size on everything smaller and closer to the original map, "戈壁沙漠" doesn't have to be broken up in the middle (since the distance between each character should be the same), and "吐蕃帝國" can cross through "喜馬拉雅山脈" like it did in the original map.
5.
Original: Wu Zetian's
Current: 武則天 的
"武則天的中國" sounds very unnatural to Chinese ears. The Chinese are getting used to such Westernized expressions, but a native Chinese is still more likely to write "武則天時代的中國" ("China of Wu Zetian's Era").
This is a bit debateable. But in the very least, the space between "武則天" and "的" is unnecessary, and should be removed.
Hope this helps! I'll also write about the map of Japan when I have time.