This is a tough topic. I think cell shaded graphics look great and they make the game age better. However due to the mentality of certain gamers, a realistic tone could generate more interest in the short term.
I think for Nintendo though, cell shaded graphics are the way to go as they always seem to be behind in console power. If they went with realistic, people would just complain that it does not look as good as Witcher 3 or Skyrim.
BotW is a beautiful game to the point where people don't seem to worry that it is cell shaded. This is possible on the WiiU because of how well cell shading ages in the first place. As far as I am concerned, this allows BotW to look every bit as good as Witcher 3 on weaker hardware, and that is the key to why they should keep using it given the circumstances. The last realistic styke release was on the GameCube, which was Nintendo's last powerful home console for its time. I think that this is no coincidence.
And Skyward Sword had its flaws, but it was a GREAT game!