It's really just the simple things that will make Nintendo's next console a MUCH bigger success than the previous two. Just NOT GIVING THE COMPETITION A *HUGE* HEADSTART alone will probably be enough. If Nintendo can do that and also have a great launch lineup and convince some of the biggest third-party developers like Capcom, Sega, and Namco to give it strong support from the start, everything else will fall into place and the next console could easily be its most successful ever.
Fortunately, Nintendo's new president Iwata seems determined to improve Nintendo's stance in the console market and I have complete faith in his abilities.