I'm very interested to see what they do with NFC.
If it strikes me as 'dodgy', ie. using the same business model as Skylanders or to a lesser extent Infinity, I'll avoid it like the plague.
Conversely though, if it's something additional to the game, I'll be all over it. For instance, if it's used as a quick unlock for certain characters in Smash. I'll pay £10 for a cool figure of, say, Young Link and to be able to play as him from the start without having to play for hours to unlock him.
Or if, apart from the 'main' NFC, game, you could scan characters into other games as one-offs. So if you scanned Pit into Mario Kart, you could play as him in local multiplayer (taking on a generic weight character). I'd be very surprised if MK8 has NFC capabilities. But that's how I'd like to see it used.