Nintendo does a range of games.  They treat Mario as a mascot and stick him in a range of games.  They use Mario in this manner a lot actually.  They will release a sports title, and use Mario and other characters they have in it.  They come up with a fighting game and Mario is it.  I wouldn't be surprised if they do an FPS some day and Mario is in it.  Then, if this title takes off, they will have a series of games, with Mario in the name, or something else.  

BUT... here we go, Nintendo does this, and people end up hating on Nintendo because Mario is it?  Why the hating on Mario?  I don't get it at all.  Can someone explain why the hating on it?  It isn't like Nintendo doesn't develop other characters either.  They did push Wario, for example, and the Warioware stuff spawned a number of new characters.  You also have the latest with Miis.  But, in a flagship title, they have Mario, irregardless of the genre, why the hate?

Probably because it ties it to a younger audience and the art direction. They could easily not put mario in some of those titles. People tend to not like milking franchises when it is done on a regular basis. People who have an issue with it probably would rather see a realistic emphasis on games instead of the cartoon-like art that comes along with mario. If they made a FPS with Mario I would hope they go dark or noir with it, a grisly mario and a rough and tumble world. Sure would be a wonderfully refreshing direction with the familiar franchise. Reiterating the same design and concepts get old.

EDIT: For example, have you watched There Will be Brawl?

Could it be moustache envy?

because it is too much. you said there is also wario and so on but you simply see they are all from the same "world". wario or luigi aren't mario but they cleary have the same art style.

i love halo and the master chief but i would hate to get a racing game with master chief, a jump&run with a grunt and tennis game with cortana and whatever. ok better than not getting them but i would rather like to see nintendo bringing more games with totally different characters with totally different art style which don't remind you that it is still just a character out of the mario world.

Because Reggie thinks we want 50 Mario games in the span of a year.

We keep shouting, "Give us more! We want over a billion Mario Games!"

Probably because he chose to star in that horrible extension of Saved by the Bell known as the College Years. That show sucked. He was cool on Dancing with the stars at least. He hasn't really done anything relevant lately though.

People dont hate Mario, Sony and Msoft fanboys hate Mario because it gets amazing ratings and lots of sales...more than they beloved "mature" franchises...its called envy

read what i wrote, has nothing to do with what you said.

To be fair, the reason people don't want Master Chief doing those things is because of the type of character he is. His personality doesn't scream tennis and cutesy cart racing. Mario is more versatile in the sense that he can transcend multiple genres. I personally prefer this strategy than your suggested one because the use of new characters in a tennis game that were only used in said tennis games would make me feel like those characters don't matter. Essentially, I would feel like I was playing a game with a stick figure. Mario and gang replace what would be just stock characters with faces everyone recognizes and enjoys anyways.

because we don't all like the same thing. Some people like Master Chief and others hate him. What's so hard to understand?