Well, out of no where, we've now learnt are pretty close to a new game in the series. In an interivew with Eurogamer back in July, which has just become public, Shigeru Miyamoto himself confirmed the game's production. He noted that the game was "very close to completion".
If it is close to completion, it's probably fair to assume that it will be released on the Wii U, rather than the upcoming NX. Though that depends exactly on how specific "very close to completion" was meant to mean. I'll let you know when this becomes official.