If we talk about Geopolitics as how people like Mackinder and Spykman are talking about it, then I think China already has a powerful and effective Geopolitical Doctrine. That would be what I would call "the balancer".
One of the biggest issue I had with both Mackinder and Spykman, is that they seems to be way too accepting and respectful of the boundary of China set by the Qing dynasty, and rather reluctant to reconsider defining most of Qing China as part of the "Crescent" (or the Rimland, in Spykman's words). I guess it has to do with the fact that detail history of China was not readily available to them during their era.
In my opinion, the boundary between the Mackinder's Pivot and the Crescent (or between Spykman's Heartland and Rimland) in the East Asia front should at least be along the Ming Great Wall. The Pivot (Heartland) should certainly include Xinjiang, Manchuria, Inner Mongolia and even the Tibetan plateau. The equivalent of Mackinder's Central and Eastern Europe in East Asia should be the North China Plain, and the North West Mountain Area (西北山区，including Shaanxi, Shanxi, Gansu, Ningxia provinces; 陕西、山西、甘肃、宁夏).
This I believe will explain everything. In a sense, China's very existence in today's world is a great balancing power. China's control of Inner Mongolia, Xinjiang, Manchuria, Tibet and Qinghai, ensured that any great Continental Power (including Russia) that wants to dominate the Eurasian super continent (the World-Island) by taking over the landmass of Russia and the rest of the Heartland, will be faced with big hole in their full circle.
For example, if a Russo-German empire were to form right now, they will need to spend a huge amount of resources, time and effort to take what ought to be part of Pivot (Heartland) from China. And that only completed the Pivot (heartland), in order to dominate East Asia, they will need to go further and control the North China Plain and the North West Mountain Area.
This means that China's very existence prevents another continental power from dominating the Heartland and achieving world domination by controlling the Rimland from the Heartland. However, China itself has shown no aspiration to be a Continental Power with the entirety of the Heartland as the first goal. In fact, China is investing overwhelmingly in capabilities that is most essential for Maritime Power. This means that China is using its geopolitical assets only to "cockblock" other potential Continental Power (Russia, Germany, etc) from dominating, and at the same time using its industrial economic resources only to challenge the dominating Maritime Power (USA and etc).
This is slightly different from the Imperial Japanese from the 1920 to 1945. The Japanese, despite being a Island nation, wanted to be both a Maritime power and a Continental power at the same time. They attacked the mainland, and contemplated invading the Heartland held by USSR. The Japanese Grand Strategy created an existential crisis for the USSR and the USA, enough to cause both of them to decide upon defeating and destroying the Japanese Empire at all cost.
