If God were to stop Satan before he even sinned.

It would have cast doubt. God would have let fear control him, and since God is not fearful he took a chance and made creation anyways.

His way of saying he's sorry is the death of Jesus the highest price he could have possibly paid.

Humanity for the rest of time will be a text book example of what happens when sin manifests.

This is the one and only rebellion ever, this possibility had to have been played out eventually since God's been around forever and will be around forever.

Now in heaven when someone asks "are your ways the best?"

God and show them what happened here on earth.

Gods ways are so mysterious he lets to "hit many birds with one stone" and always with love.