WHY THIS?
This is just an interesting question. Of course, if we are less than omnipotent, no alternative we can conceive will adequately answer this query.
"Let us fix our eyes on Jesus, the author and perfecter of our faith, who for the joy set before him endured the cross, scorning its shame, and sat down at the right hand of the throne of God."
- Hebrews 12:2
"If God is omnipotent, couldn't he have found a less horrific way to carry out his plan than the cross?"
"But he was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed."
Isaiah 53:5 NIV
"...He Himself bore our sins in His body on the cross, that we might die to sin and live to righteousness; for by His wounds you were healed. "
1 Peter 2:24 NASB
RESPONSE:
I'd better say I don't know. Being neither omnipotent nor omniscient myself, I am hardly in a position to judge God's alternatives or the choice he made. I will say that God's willingness to take upon the horror of the cross may serve as an illustration of the awfulness of our sin, and the lengths God is willing to go to save us. It does do that.
Additionally, the word omnipotence must be carefully understood in regard to how it describes God. There are things God cannot do. Among those include: God cannot act contrary to his nature, he cannot overlook sin, he cannot tolerate injustice forever, he cannot break his promises, and he cannot lie.
See also:
God, evidence, and atheists
What were sacrifices all about?
Expanded!