I recently wrote a few [https://snakecharmers.ethereum.org/the-winding-road-to-functional-light-clients/] blog [https://snakecharmers.ethereum.org/the-winding-road-to-functional-light-clients-part-2/] posts [https://snakecharmers.ethereum.org/the-winding-road-to-functional-light-clients-part-3/] describing what was needed for us to have truly functional light clients.  If you haven't read those, you should go do that now. I'll