I think it would've been better overall if Luke and Leia had been born before the confrontation on Mustafar, and if Padme was killed outright by the Force grip. I'm not sure where Lucas got the idea that this obscure "will to live" business would be better than the alternative, and I've no idea what he was trying to imply with it.
"Grant Allen [...] had written a book about the Evolution of the Idea of God. [...] it would be much more interesting if God wrote a book about the evolution of the idea of Grant Allen." ~ G. K. Chesterton, The Everlasting Man