That's what Nintendo needs to get right. A big, appealing game every month for 6 months would really get some momentum.
Remember the first DS? After the launch buzz sales were pretty low, then after almost a year they released a succession of compelling titles in fairly close proximity and it was smashing success.
I know DS development is cheaper and faster, but it might just be time to bite the bullet and throw some cash around to get the ball rolling. I also think that Nintendo should consider releasing games with more obvious numbering. Like MK8 - obviously the latest release in the series. There is too much history and giving games subtitles and adding "New" or "U" doesn't always make it obvious that a game is a major new piece of software, rather than a re-release or HD compilation or something.