I'm not sure fans are asking for epic or are rejecting casual games (well at least the sane fans). I think what's frustrating for Nintendo fans is when Nintendo started pandering their franchises to the casual crowd. That's why sequels like Mario Kart Wii suck. They simplified the game specifically for people who don't know better or care. And sequels like Twilight Princess are almost parodies of what fans have been asking for. It's dark... so f*cking dark and mature... there's death and fire and cleavage... but the game is easy as hell, derivative and so long that it's boring.
Truth is, you can make an engaging game that's fun, beautiful, and original without spending millions upon millions of dollars. Does Zelda need 15 minute FMV cutscenes that take months to produce? No. Nintendo (or anyone), if they really wanted to, could easily create a deep storyline without delving into melodrama (nearly any scene involving Zelda in Twilight Princess) or insulting the audience's intelligence and they could do this without all the bells and whistles Square-Enix and Konami thinks are needed to tell a good story.
Didn't Nintendo try to cater to the hardcore audience in the final years of the Gamecube's life... ...So you can't say Nintendo didn't try...
Dude, seriously.... That's like playing hard the last minute of a game when you're already down by 40. Nintendo practically did everything they could to make hardcore and mature games fail on Gamecube... you can't chime in at the 11th hour and act like you gave a sh*t.