Something tells me...this is the reason why Smash Bros is pushed back until Winter. I bet Nintendo wanted this game as a summer release, but then decided to add this new strategy into the game.
So the question is what can we expect from these NFCs? How about 1-3 real miniature trophy packs. Perhaps with 2 new assist trophies and 1 new character and level? Sounds unlikely, perhaps, but SOME of the new characters could just be modifications to existing characters.
For example:
Luigi with a full Luigi's Mansion move set.
Doctor Mario with pills floating different than fireballs
Wolf, Falco...ect being Fox clones are a good idea for figures.
It would be an interesting way to handle downloadable content, because you can get a figurine, charge more, and have parents feel they are getting tricked into in-app like purchases.