Who will benefit from regional leadership rivalries?

Comments on Aurelia George-Mulgan “Hatoyama’s East Asia Community and regional leadership rivalries”, 13/10/2009, http://www.eastasiaforum.org/2009/10/13/hatoyamas-east-asia-community/

A couple of comments.
First, it is interesting that why an East Asian community should include non-East Asian nations to begin with. If it is open regionalism, why should it be called East Asian as opposed to Asian community?
Second, from a strategic point of view, it would be interesting to see which, Japan or China, will benefit from delaying an East Asian Community. This is especially pertinent in the context of the so called G2 potentially. In that context, there is no middle powers represented.