Notice that the only 3DS games announced from any third-party are ones that have already released in at least one region? This pattern holds for Wii U as well (with only a few exceptions, most of which are games that got delayed from 2013). If it were just the Wii U, I'd think that publishers are just stopping support because of weak sales... but this cannot explain the situation with the 3DS.
I honestly suspect that Nintendo has had publishers keep all of their 2014 titles secret, for some big unveiling, or something like that. Consider that neither Sega nor Ubisoft, both of whom have been supporting Nintendo very strongly, have anything announced for 2014. A similar thing can be noted regarding Namco Bandai and Tecmo Koei, both of which have supported Nintendo quite well, and both of which are co-developing titles with Nintendo.
A similar thing could, perhaps, be occurring regarding the Vita, but I haven't paid close enough attention to determine that. But I'm pretty confident that both the 3DS and Wii U have a significant number of games set for release in 2014, but not yet announced, possibly even games set for release in the first quarter.