One thing big with this concept is the feel of the game. The player with every new life wakes up in a life he doesn't know. Imagine Quantum Leap.

yes. like Ring, too. That game about the Niebelungenlied, Wagner symphonic cycle. You had to work your way through four different stories, linked only by the saga. You could come back to the "core" at any time, and switch to a different story. At least, it had Wagner's music for it...

What could be cool with an idea like this would be simulating the passage of time. You could start each character's life quite young like six or so. Then it takes 15 or 20 hours of game time till you age to 16 and the enemy finds you. In that time you are free to explore the sandbox world in that era and gain as much power as possible. Any major effect to the world could then pass over to the slightly future world that the next character lives in. Don't know if that makes much sense but it would be a pretty nice way to play.

The game time progresses as the story does. In the first scene, the main character is a child when the witch starts the hunt. He is forced to flee into the planes through a portal opened up by the enchantress helping him. (at this time he believes her to just be a childhood playmate. This is all in the opening story.

The first world, takes place immediately after the initial cut scene.
The player plays through this world as until either the character's natural death, or until he does "something" (undefined att) to draw the attention of the witch. At this point he flees into the second world.

In the timeline the character starts over again at around age 16, and again continues on until the same set up as before.

Repeat for world three.

At this time the character begins life (age 16) in his final body. He slowly learns of his history, and his powers (all learned in the previous worlds.) after about 20 years in this world, he gains the ability to traverse back to the worlds his previous lives were in.

In the first world, almost 3 generations have passed since he lived a life there, people have moved on from whatever major events happened, and his character is generally reguarded as folklore. Descendents abound

In the second world, 2 generations have passed. Adults he knew are gone, and children he knew when he was old, are now old themselves. He may be able to meet his great grandchildren.

In the third world, its been only about 40 years since his life there ended. The world has moved on about as far as we have from Vietnam, some places have healed while others have not...

What do you think?

That sounds great actualy, so lots of freedom at the end to play with all the goodness/havoc you spread in the past bodies? That could be really fun...