Based on the below quote from a GameStop interview:
GameSpot:“Is this the biggest team you’ve worked with, and is this the biggest team that’s ever made a Nintendo game before?”
Aonuma: “Yes, to both questions. There’s a lot of people.”
Nintendo is stating that Breath of the Wind is one of the largest productions the company has ever put out. Considering we reported the large team at Monolith (Xenoblade) is working on the project with Nintendo’s core Zelda Team, this shouldn’t surprise anyone.
Still, it is nice to see such confidence in the game and we can’t wait to report more on the game as news on the title comes out.
Source: Zelda Informer