Ah, and the rose-colored glasses come on. Nintendo began franchising out Mario as early as the SNES era, the last major franchise created besides Pikmin was Pokemon in 1995, and it was the Yamauchi regime (actually the man himself) that shot Nintendo in the foot by screwing over Sony about the Playstation and setting up their biggest competition to steal everything away from them for the next decade until he was forced into retirement. Since then, Nintendo's moved to number 1, has two great consoles out, and awesome games for almost every franchise available for both of them (screw it, I liked Star Fox Assault & Command).
Your Mario RPG example is idiotic. The second Mario RPG was totally different because Square wasn't working with Nintendo in the late 90s, not because of executive genius (though it showed how talented Intelligent Systems was), and the fact that the games got sequels doesn't mean the predecessors were being diluted; they were just telling more stories in the same style. Would you want Sonic the Hedgehog to have stopped at the first one lest Sega "rehash" their previous success?
And about franchise themselves...look, the games are fun. The industry is supposed to be about fun, and if all of Nintendo's games are well-made and try new things with each installment, what's the problem? At least they're not like the rest of the industry, which produces about 1 good game out of every 15, and even those usually lack much personality. "Core gamers" can bite me.
The presentation sucked because all I expected of them was to announce a new Zelda game, and they didn't even do that. What's the point of even doing these things if you're just going to let down your customers?