On the other hand, cynics and jaded analysts are sceptical that the new leadership under President Xi Jinping can overcome the resistance from powerful vested interests and strong ideological wrangling within the party to achieve a strong enough consensus on which political reforms are necessary.

They believe that the much talked-about key reforms to break up state sector monopolies, abolish the household registration, and change land ownership laws will hardly be revolutionary, but, when announced after the plenum, will be watered down versions to bring only gradual changes.

Both views are valid but lopsided. Great optimism about the outcome of the plenum has stemmed from state media reports and senior officials including Yu Zhengsheng , the fourth-ranked member of the Politburo Standing Committee, promising "unprecedented" reforms.

Also stoking hopes was the disclosure of a detailed reform proposal known as the "383 Plan" in the run-up to the plenum. It was drafted by some of the top leaders' most trusted advisers, outlining a detailed road map to rein in government and free up the market, including a timeline to make the yuan fully convertible and measures to allow farmers to sell their land.

But such hype needs to be taken with a pinch of salt. The reforms launched 35 years ago to open up the country have reached the deep-water zone, to borrow a Chinese saying, of "feeling the stones to cross the river". This means that any step forward, big or small, will be unprecedented by Chinese standards.

Second, judging by leaders' ways of doing things and drawing from party history, such plenums mainly aim to achieve consensus over the tone and direction of reforms and agreement on the very broad objectives of how to ensure healthy, sustained growth.

The four-day meeting will, no doubt, see intense debate over how to encourage market competition, entrepreneurship and household consumption while reducing the role of the government in the economy. But the communiqué is unlikely to include details on how these goals will be achieved. That will come much later.

By the same token, it is equally wrong to underestimate the determination and wisdom of Chinese leaders to push for drastic reform.

The mainland leadership likes to boast of their foresight and courage in undertaking changes to transform the economy into the world's second largest.

But history has shown that every time officials have agreed to push for significant reforms and move the country forward, it is usually because they had their backs against the wall and there was no other way out. That usually meant that the economy was at a critical juncture and the legitimacy of one-party rule was being severely tested.

At the third plenum of the 11th Central Committee, Deng Xiaoping adopted the open-door and reform policies when the economy was on the brink of collapse following the disastrous decade of the Cultural Revolution.

A similar fate awaits the leadership as China's breakneck, double-digit growth of the intervening 35 years is no longer sustainable and the legitimacy of the party is being increasingly challenged because of rising social discontent over corruption and other social injustices.

Again, as history has shown, Chinese leaders can overcome their differences of opinion and make certain sacrifices of the vested interests they represent to achieve consensus on the best way forward - just like the decision to open up to the outside in 1978 or to join the World Trade Organisation in 2001.

Tomorrow's communiqué may just be the first indicator of the new leadership's intention and goals.

A more important indicator to watch is how quickly those ideas are transformed into policies and how successfully they are implemented.

This will only become apparent in the coming months.