I agree that we've seen Nintendo definitely pull away from the traditionalist gamer's view of how to do hype and marketing. As enthusiast gamers, we want new announcements, plenty of hype, and things to basically over-excite our brains with possibilities. However, I think you're right in that Nintendo thinks that a more cost effective way to market their games is to do it on a different time-frame, and a much tighter, focused, pertinent-to-actual-release launch cycle.
Whether that will bear out true is yet to be seen. Certainly when viewed from a traditionalist sense of how we're supposed to get excited about videogames - reading magazines previews, watching trailers, etc. - for up to two years before a game comes out, it doesn't make much sense. One argument that could be made is that early adopters at launch are heavily enthusiast leaning, so without a more traditional discussion about their upcoming library Nintendo may be making the wrong "launch advertising" buildup play. Of course, one might also argue that Nintendo's early adopters are a different bunch than regular tech enthusiasts.
There's also the possibility that Nintendo had games and announcements they could make at E3, but they're holding them off for other soon-to-come events due to scheduling issues, deals with other companies, or because they opted to polish the projects off more first.