* Chinese stock indexes slide, dragged by state-owned banks

* China upgrades markets' role in economy to "decisive" from "basic"

* Conservatism on state industry reform risks further distortions-economist

* State media editorial warns of "vested interests"

By Pete Sweeney

SHANGHAI, Nov 13 (Reuters) - Unimpressed by the promotion of markets to a "decisive" role in China's reform agenda for the next decade, investors sold off Chinese shares on Wednesday, disappointed by a lack of details in the reform plan and apparent reluctance to overhaul the state-owned sector.

The ruling Communist Party said at the end of a four-day conclave of its 205-member Central Committee on Tuesday that it aimed to achieve "decisive results" by 2020, and gave markets a more prominent role.

By setting an unusually explicit self-imposed deadline and establishing a special working group, the new administration of President Xi Jinping and Premier Li Keqiang suggested a more decisive reform push than under the previous leadership.

But while the communique mentioned several reform areas Beijing aimed to tackle, its language was even more general than some had expected and it explicitly underscored the importance of the state sector for the economy.

"State-owned enterprise reform is a big disappointment," said Gary Liu, deputy director of the CEIBS Lujiazui International Finance Research Center in Shanghai.

"But the implementation will be even more important than the plan itself."

All major Chinese stock indexes opened down, lagging Asian shares.

By 0230 GMT, the CSI300 index, which tracks China's largest listed companies in Shanghai and Shenzhen, was down 1.4 percent and the Shanghai Composite Index was off 1.1 percent. The index of Chinese enterprises listed in Hong Kong fell 1.8 percent.

All the indexes were dragged down primarily by financial stocks, in particular major state-owned banks, seen as the key levers through which Beijing controls the economy.

Other Chinese financial markets were flat, with the yuan trading steady and short-term money market still dormant at time of reporting.

Global markets also gave the outcome of the conclave little attention, focusing instead on when the U.S. Federal Reserve might start to rein in its economic stimulus measures.

Investors have been waiting for the official statements of the party meeting for signs of the government's intentions toward both financial markets and the companies that participate in them.

Explaining the new approach to reforms, official news agency Xinhua said in an editorial on Wednesday that rather than playing a role of markets in a system dominated by the state, the government would seek to accomplish its goals in conditions determined by markets.