The main tactics that China would or should employ when dealing with potential adversaries would actually be determined by the capability of her opponents.
For potentially weaker opponents such as North Korea and Vietnam, an armoured thrust into their capital might be useful but very wasteful of China's troops. Thus the main tactics would be to employed the vastly superior air-force, missile force and Navy first... doesn't actually need to be destroying all their important assets (if possible to destroy their infrastructure and assets, it would be the best result) if not it will also serve to lower their troops morale, bring fear to their normal citizens. Only after these objectives are reach then, the armour would be used to thrust into opponent's capital.
As to adversaries like Japan and South Korea, the main tactic use should be their missile force, to knock off as much as possible, the opponents' important assets and break down their basic infrastructure, before sending in the air-force for surgerical strikes. The infantry and armour should only move in at the later stage of the war.
At present moment, China is still not like US, who could afford extended period of operation at faraway areas, thus their best bet is to move in quickly, achieve their objectives and leave the place.
Heavy armour that are slow and basically not able to travel in most of the roads, terrains and bridges in their opponents nations are useless. And if these tanks are actually used only as defensive element back in China herself... it was basically not required to do so... because many of the country's terrain also make the tank quite difficult to operate.
Thus I believe Type 99 (basic) is enough for its current job, instead of jumping up the tonnage and having a much bigger gun.