It's all just chance, right?
Yes. My understanding is that to God our physical appearance means nothing. To a Christian God it is the disposition of our souls that matters. The body is corruptable and this life is a station on the way to bigger and better things. Ultimately it is not the body but the soul that lives. God is expected to make new bodies anyway.
Now, if God gives us intellect, because it matters to him, does that mean all the stupid people are bound for hell, or do you think your next door neighbor in your heavenly condo with a view will be some Darwin Award winnder with baby blue eyes? In that case, what is God's IQ heavenly pass cutoff score?