I think that you're trying to find a solution to a problem (Satoshi's rewarded addresses whose public key is exposed) and you introduce others by doing so. Of course, consensus is required to enable this. What I'm telling you is that the users will never come in an agreement for it due to its utopianism.
I think stealing non-moved coins is really dumb and not needed, and nobody will agree to this idea.However, I think it might be interesting to explore the idea of 'empty blocks' in the sense that if all utxos are spent, you don't have to keep them in the Blockchain.
But in general, all this topic is really 'trying to find an idea to a nonexistent problem'. Recently, someone brought to my attention how many people now have a 256GB phone. While the Blockchain is sitting at a bit over 300 gigs. The 'flippening' (
) is probably happening very soon where it will be normal to have enough space on your mobile phone to store the entire Bitcoin blockchain if you wanted. At that point, it will be an absolute no brainer to just run a full node on your multi-TB all-SSD PC or laptop at home.As long as the Blockchain grows slower than storage for a given price (which it is) we don't have an issue to try to solve here.