someone once said 'Song is most offensive defensive midfielder in the world'. IMO, he's better than Barton. But my opinion is that Barton would fit well in Arsenal system. Wilshere as playmaker, Barton as holding midfielder and Song as tackler/connection between defense and attack. Wallcot and Gervinho on wings and RVP in the middle. Sonds good to me. Arteta is similar to Ramsey and Wilshere, but since Jack is injured, Arsene needed playmaker.