Face value? I'm referring strictly to mechanics, not graphics or music. Level design is important. And guess what defines level design? The gameplay mechanics.
SMB2USA was extremely influenced by the different abilities of the characters as well as the unique interactions with enemies and items. SMB3 level design was defined by the ability to be a raccoon. Donkey Kong '94 even had level design that was built with the new moveset available to Mario.
NSMB, by not innovating mechanics, has less of a chance of innovating level design. The levels can be good, but they will likely play quite similarly to the other titles.
Regardless, Pikmin 3 needs to be launch. Delay NSMB:U. It doesn't need the launch help.