http://www.polygon.com/2014/3/28/5555682/animal-crossing-interview-new-console-version-smartphones
"The current gameplay style of Animal Crossing is best suited for a portable device," Eguchi said, "but if we were to create an Animal Crossing for a home console, I think we would really have to invent a new style that's suitable for the platform. The environment in which the player is playing the game is very important, so we need to think that through before we start creating something like that.
"We might not have been able to do that for Wii," he said, "but whether it's the Wii U or a future hardware, it's important to think about what environment the player will be in."
To me this sounds like while they were considering a Wii U version, this thing is going to end up on the next handheld. Nintendo does not casually mention "future hardware" like that in interviews all that often.
I think AC being on Wii U was largely dependant on Wii U sales exploding post-MK and Smash, and while they are better, they are still mediocre.
Which likely makes this a fairly easy decision for Nintendo.
Animal Crossing + Mario Galaxy 3 is a can't miss 1-2 launch window for the next Nintendo handheld. If Nintendo is smart, they will do that.