Yes, but I think he was only talking about nodes. I don't think utxos can be gotten rid of, but maybe there's another option than holding the utxo set in ram. Idk, maybe he'll clarify
That partial index sounds good. Are there any other options?
Discussion
It's tough to wrap the mind around but memory maps are very fast to query and don't have to have a list of UTXOs. On a per block basis, "is the coin being double spent?" and "is the coin there(in the spending address)?" solves the issue of needing to know where all the coins are simultaneously.