kind of a harsh word dont you think?

I beg to differ, NSMBU is the one of the few reasons the Wii U actually managed to move consoles this year. Together with Nintendo Land it is by far the best selling game. NSLU could easily be the 3rd best selling game if the download version had been included, it was released earlier and had a cheaper price tag. Super Mario 3D World has so far given a percentage boost similar to other Mario releases. When Galaxy was released Wii sales jumped 63% in the US, with 3D World they jumped 61%.
None of the games you mentioned have actually flopped.

The game is fantastic and deserves better, but I do want to see a more open Mario game.

Maybe a bit. But I've always likened the casual audience to the hot Paris Hilton wannabe girl at the night club who loves to party and post selfies on Twitter all day. She's rich, good looking, young, and knows it. 

Nintendo one day is the "nice guy" at the bar who just got fed up with not getting any attention from girls that he decided to start dancing like a mad man and became the life of the party. To his shock, he even caught the eye of Paris Hilton Girl and they partied together for a night. 

But alas, at heart, Nintendo isn't the guy Paris Hilton Girl wants. He wants a relationship, Paris Hilton Girl just wants a fun distraction, she has 10 other guys always orbiting around her trying to impress her, but really the only guy she really wants is Apple (the big time alpha male). 

Nintendo shows up at the nightclub the next week hoping to impress Paris Hilton girl but finds she's "over" that as she has the attention span of a 6-year-old and barely acknowledges him. 

Nintendo wanted a relationship/marriage type situation with casuals, casuals just want to "party". Nintendo got suckered in by the rush of those casual profits, not realizing it wasn't sustainable. 

In my oppinion 3D world sells good!!

So basically, you don't mind if the people who like the 3D series games never get another Mario like it, as long as you get another Galaxy, which by the way, if you've been paying attention, they've already said that haven't forgotten the Galaxy games, which, based on fan reaction, is all but assured. We can have both, and likely will, so don't completely shut down the people who like 3D Mario different then you,

Can we say for sure that it is a commercial failure? We still don´t know how much it sold digitally

Let´s wait until the holidays. if it sells about 1 million copies it should be enough to give Nintendo some profits

It will sell 3 million minimum LTD, c'mon now. Mario games sell for a long time, most people buying a Wii U over the next year will be getting this game with the system. 

Virtually every Mario game Nintendo makes likely turns a handsome profit, even things like Mario Tennis and the Mario & Sonic Olympic games. 

It´s not selling as much as Nintendo wanted, or needed, but it´s selling enough to be financially sucessfull.

That´s the point that people here don´t understand: Nintendo doesn´t need to sell zillions to make profits, they don´t need to be the first. If their console sells about 30 million units lifetime they will be ok.

I do believe that you´re right. Mario always will have appeal to some consumers, we just have to look of its latest installments. Even NSMBU managed to sell 2 million + and will eventually hit 3 million with digital sales.

People here are too blinded with fanboyism no notice obvious things like this.