It's not that black and white. It was Deng's regime that crushed the Tiananmen Square protesters. There were other nominal heads-of-state at that time, but Deng had de facto power.

His reputation is generally favourable today because of the economic wonders he orchestrated in the 90s.

Depending on how you define a good politician, Zhao Ziyang, the party general secretary in 1989, was sympathetic towards the pro-democracy movement. But overall he didn't change as many lives as Deng did. He lost power after Tiananmen Square protests.

One liberal political who was pro-democracy at that time yet still remained in power is Wen Jiabao, the current Premier (second in power maybe). He is probably the most popular politician in power today. If there is going to be top-down democratisation, it would probably start around him. He is in a lineage of politicians who rose to power through meritocracy rather than loyalty, succeeding Zhu Rongji.

http://en.wikipedia.org/wiki/Wen_Jiabao