Well, He would have had to do things differently, starting with killing two animals to make coverings for Adam and Eve. He established right there that the covering of sin requires the shedding of innocent blood. I can see what you're saying, from the standpoint of God's omnipotence, but I believe He did things as He did for a very definite reason, it wasn't just choosing between several different options. Even in the Garden of Gethsemane, Jesus was asking if there was another way, even though He knew there wasn't. I see two things there: Jesus revealed His total humanity at that moment, He was a human as you or I in not wanting to go through all that pain, but as God, He knew it wasn't possible to avoid it. He had to settle the question in His flesh at that moment. The second point is that even an omnipotent God was constrained by the task and duty that lay before Him. He chose this path before the foundation of the world, when all that is was just a gleam in His eye, a thought in His mind.
I find it disturbing to think that God could have done it some other way, or not done it at all. I'm glad He did it, otherwise, we'd be in deep, deep trouble....
Not doing it at all is a scary thought. But if God had had a better plan, it would only be one that would be even more majestic and glorious.
SD