The Ainur and the Children

[The Saucepan Man]

To prevent any new evil from occurring, not only would evil have to be removed, but also the inherent potential of anyone to become evil.

Which, as I see it, would involve Eru removing His Children's free will. Which He would surely never do since, well, what would then be the point of their existence? So, while Arda may have been Unmarred, wasn't there still the potential for one of His Children to choose to rebel against Him and go about Marring it all up again, just like Melkor did all those years ago?