Soundwave on 06 November 2014
If you actually look at Nintendo's handheld release history since the GBA SP, they release a new handheld model/revision almost on a yearly basis and have for a while now.
2003 - GBA SP
2004 - Nintendo DS
2005 - GBA Micro
2006 - DS Lite
2007 - nothing
2008 - DSi (Japan)
2009 - DSi (West), DSi XL (Japan)
2010 - DSi XL (West)
2011 - Nintendo 3DS
2012 - 3DS XL
2013 - 2DS (West)
2014 - New 3DS (Japan)
2015 - New 3DS (West)
2016 - Fusion (?)
A new Nintendo handheld in 2016 wouldn't be anything out of the ordinary, in fact it would match up perfectly with their usual release cycle.
