The best thing AI could do for us, the absolute best, is help us understand ourselves fully, down to the roots of suffering, joy, meaning, and consciousness… and then help us rewrite that structure. Suffering is the right target because Darwinian evolution built us to feel it but never to escape it: pain, anxiety, and craving were selected to keep our genes, not to be livable. Gratuitous suffering is not necessary and it should be possible to get rid of it without erasing joy and meaning.
We should ask for more than to: automate labor or cure disease or generate infinite content, or even solve physics. Those are side goals. The main goal is this: use intelligence to diagnose, modulate, and ultimately liberate the human condition.