User blog comment:Tadmonkey/Wii U/3DS Connectivity Characters and Stages Leak?/@comment-25466413-20140927083857

This leak sounds so much like…Sakurai.I don't know if you also remember this but sonic was added only because people requested him. So they added him late.So maybe Sakurai left some characters out because of time constraints and is putting them in the Wii U version so you can unlock them by connectivity between Wii U and 3DS.