It is possible that Aonuma was held back creative-wise by Miyamoto, but he does share the same philosophy as Miyamoto when it comes to games and difficulty. I actually respect Aonuma for finally doing something new to the Zelda franchise with Phantom Hourglass. It it were up to Miyamoto, it would probably end up being another
OoT/
ALttP clone.
Anyways, I can see this whole difficulty thing becoming a problem. They aren't just creating new franchises that are easy, they are also taking the "hardcore" franchises, and dumbing them down so anyone can play. At least that is the impression that Miyamoto is giving away.