A killer app, by definition is, in this context, a game that both sells well and that substantially increases the sales of the platform(s) on which it is played. Thus W101, while it may be a fantastic game in the eyes of some people, can in no way be considered a killer app.
Wii U doesn't have a killer app, and that's why it's selling so poorly.
That said, it's possibly true that certain types of games will never land well with reviewers because they don't "get" the game. Same as movie reviewers, certain types of movie will never get great reviews because not enough reviewers like that sort of movie. However it doesn't stop those movies from doing very well at the box office, because the movie is loved by the genre fans.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
