The Legend of Zelda: Breath of the Wild is an ambitious game, but this comes at a price. The game might not make the Nintendo Switch March 2017 release window.
Well known Nintendo Insider, Emily Rogers, posted on her blog that The Legend of Zelda: Breath of the Wild is taking a long time to get localization finished. After localization is finished in December 2016 (their target), a further four to six months is needed to test everything out.
Eurogamer has heard from their own sources that of a similar development story. They say Nintendo wants to release the game as perfect as possible without any hiccups.