If Cafe is announced then it is possible that Wii's sales will fall significantly. But you can never count out those Soccer Moms or Retirement Homes from picking one up. If 3DS gets some decent software and promotion it is possible for sales to pick up dramatically.
PS3 or 360 price cut before the holidays will change a lot. I doubt NGP will have much oof an effect on the 3DS
It's not possible it's a certainty that they will drop about 90% from last year. With zelda coming they may sell a few units more, I don't expect 3DS to pick up that much due to high price.
Buying in 2015: Captain toad: treasure tracker,
yoshi woolly world
majora's mask 3d