I found that the brutal save system really just detracted from the game without upping the difficulty. For those (not really myself, by the way) who have only scant minutes in a day to spend quality time with their DS, little is more frustrating than just having blazed through a tough chunk of the game only to be forced to shut it off without a saving oppurtunity due to other obligations. And if Nintendo seriously expects them to have the system in sleep mode almost 24/7, they're truly being retarded... wheelchair-bound... political correctness will be the death of us... special. NSMB wasn't a particularly challenging game by any means, but the saving system is unreasonable for, say, first-time Mario players who can barely make it to a world's halfway Tower without a game over. Even as a seasoned Mario gamer, I believe that saving just about whenever is essentially a "right" which game programmers should never deny us.
Imagine if the next Zelda title only allowed saving after one of the game's, say, seven or eight Dungeons. Eughh.