First Who could really fight the PLA in the PRC? To the west (India) is high mountain country where heavy armor fails by being to heavy for roads and to rbbed of power by thin air. To the south is marshland and jungle where heavy armor suffers from bogging down and getting stuck in trees and mud with poor roads. to the east is the pacific where heavy armor sinks. about the only good tank land is the Gobi, and parts of the north land( Mongolia). but they run into the frozen marsh of (Russia) Siberia. Heavy armor is good if you have a good flat plains and open space to maneuver. Heavy armored units are fine if you intend to fight at home or at fixed locations.
Light can mean reduced weight armored vehicles, but it can also mean reduced sized deployment elements. Brigades and Regiments as opposed to divisions. It's easier to move less vehicles at a time.
You forgot the central asia border to the west. Regardless, just because you dont have good terrain, that doesnt mean that heavy armour arent useful/necessary. They are, armies just have to know how to use them. Also choosing the time of the year can negate the weather adversities. Why do you think india choose the month of december to advance over east pakistan? because it was the dry season.
Dated information. When compared to modern tracked IFV's many modern Tracked and Wheeled armored vehicles are in fact the same weight with the same armor levels with the same weapons load outs. They can also carry the same number of troops if not more.
Check this globalsecurity article. See what they say about wheeled vs track.