Well ... I'd be a little worried if I was Nintendo, but really at this stage what can you do? Tablets/smartphones + kids is simply a runaway train.
If the game actually look exactly like the PS3/360/Wii U versions ... I think we are definitely getting closer to the day of a Nintendo handheld pumping out Wii U quality graphics too. So from a Nintendo fan POV it's kinda neat in that way even if its bad news for Nintendo as a business.