While I completely agree that the 8-bit Japanese Super Mario Bros 2 was not a good sequel (unlike the west's Super Mario 2, which was delightful), I disagree with making that comparison to what the "New" 2D Marios are, as they are very good, if not quite as great as they could be, perhaps.
Furthermore, regarding NSMB2 specifically, it has already been established that the more "junior" designers worked on the game while the "senior" designers are working on the WiiU version, so we don't yet know how extraordinary NSMBU (or its sales) might be.







