Note the "UU" there. Mew is UU: it only has written strategy for OU and Ubers. I don't know why. Biggest jump has to be Espeon for Magic Guard (NU to OU); that's the biggest jump possible without going from NU to Uber, which really can't happen; Speed Boost didn't save Sharpedo, for instance.
For those of you starting topics about the PS4, there's a PS4 board: http://www.gamefaqs.com/boards/691087-playstation-4