So, who came up with the idea, and what IS the idea?
In the beginning, there was Void, and the great Miyamoto… Ah, it goes something like this: Shigeru Miyamoto, the series’ head dude (also responsible for the Mario series and various other games) says in many interviews that his goal with the Zelda games is to create a virtual garden to explore. That’s basically the idea, though I can’t cite any source where Miyamoto describes the Zelda idea in detail.