By then, it was too late already for Hu-Wen. Jiang's chosen people were all in the top posts. Hu-Wen has already become a lame duck in the eyes of generals. More importantly, Jiang might have given up the post, but his influence was still very big in the military. They owed their allegiance to Jiang, not Hu. Is it any surprise that the military is corrupt if the commander in chief is a lame duck?

Besides, Shanghai clique that Jiang led is notorious for corruption. They are in bed too deep with businesses. I'm not surprised that the corruption is also widespread in the military that is heavily indebt to the Shanghai clique. Shanghai clique is also very powerful and very influential in politburo, to the point that it was hard for Hu-Wen to even appoint their people to posts or carrying out the policy, again the result is the rampat corruption in civillian gov. Jiang did a lot of good things during his time as you mentioned, but that doesn't change the fact that he has harmed Hu-Wen administration. Besides, I attributed a lot of good things in Jiang's time to Zhu Rongji.

Anyway, with politics, it is hardly to find spotless person, there are always some dirts on the top politicians, it is a dirty world after all. You don't want your leader to be a nice guy. You want them strong and can lead your nation through thick and thin.