Two comments: 1. I don't think the fact that Cabinet Ministers make questionable comments is new or surprising or a DPJ-exclusive feature. This debate reminds me of the issue about ideological diversity.
Once one looks at the history of LDP-led governments, it is easy to see that those things have happened and probably will keep happening in the future. Remember Nakayama Nariaki? He served as Land and Infrastructure Minister in Aso's Cabinet for three days, before he had to resign after criticizing the teachers union as 'cancer' and suggesting that the struggles surrounding the construction of Narita were only initiated to gain more profit from selling the land.

2. Granted Hachiro is a high-profile member of the Yokomichi/Old Socialist group and closer to Kan than to Ozawa/Hatoyama, but the party unity strategy has already backfired, if you ask me. Yamaoka keeps hearing questions about donations from multi-level marketing firms, while defense secretary Ichikawa freely admitted he was anything but well-versed in defense policy.
Meanwhile, Hirano had the nerve to argue the opening of the Diet for only four days was due to the Cabinet not being ready yet. All three were brought into the Cabinet and the party executive to pacify the Ozawa and Hatoyama camp. However, Hirano's stint as Chief Cabinet Spokesman had already been heavily criticized, while the other two gentlemen have little experience other than in supporting Ozawa. Noda may have (temporarily) solved one problem (i.e. pacifying Ozawa and Hatoyama) with his personnel management, but probably created another one that way. At least he now seems intent to replace Hachiro with somebody who has more experience.

Best,
Chris

Chris Winkler, PhD
Senior Research Fellow, Social Science Section German Institute for Japanese Studies (DIJ) Tokyo