Something else that is vital to Zelda is that everything fits together seamlessly. This isn't easy to explain, but what I mean is that with all of the ideas in the game tightly woven together, the various elements of the game will perfectly complement the terrain and scenery. The balance of "sparsity" and "density" in the game works really well. This is something that's important in Zelda. A real challenge with Twilight Princess was that as development moved from the earlier stages into the latter half, that balance was lost. The 3D Modelling Team was steadily expanding the size of the game, but the actual content of the game was not keeping pace. The longer the 3D modelling and the content remain out of step, the emptier the game becomes. Or, game content starts interfering with other content and spoiling it. Trying to get that under control is a real challenge. Putting it another way, perhaps it's controlling the balance of "sparsity" and "density" that actually makes a Zelda game. Maybe this isn't limited to Zelda... Maybe it's the "Nintendo method" of making games...