I think Google's plans are ideal.
They want to digitise all the books in the world. Rights holders will have to opt out if the do not want to be included in the programme.
Think about it. Even if ALL the rights holders opt out, Google will still be left with millions of Orphaned Works that rights holders don't care enough about to want to opt out, or there are no rights holders left to object to the digitisation.
Its a win-win for both Google and readers alike!