Neo's significance to the Machines

Is Neo there only to carry-out the function of the One and restart the cycle? If so, do they need his code to reload the Matrix like the Architect said?

If yes, then I'd assume this was what happened to Neo at the end of Rev, and he couldn't of died right away. All that light bursting through him (despite the spiritual aspect) was a little too much to happen if all they did was pull the plug. Even if he was connected to all the Smith's, all that had to be done was unplugging Neo, and it looked like they went through a different process when Smith was destroyed.

um actually i don't think the matrix is starting over becuase zion wasn't blown up, neo beat the whole matrix game.

The light was depicting both the deletion of Smith and the insemmination of the code within Neo which reloaded the Matrix and kept the system from crashing...this is why we see the cat and the Matrix suddenly alter....