This can save the day.
I've casually proposed this for Bitcoin in the past, but there's no way that something as experimental as this would ever be done in Bitcoin without at least a successful altcoin example, so it'd be cool to see it implemented in an altcoin, if any altcoin devs are interested. I have not rigorously examined this scheme for any flaw, so maybe it won't work well at all, but maybe it will.
One problem in Bitcoin is mining centralization. To solve this, I propose that the PoW be changed to the following:
~snipped~
If his proposal ever gets implemented
As theymos himself said, this is highly experimental and would require at least one altcoin implementation to test the scheme in practice (personally, I think that two independent implementations would do even better). What right now seems to be more important is the recognition of massive Bitcoin mining centralization, something that many posters flat-out disagree with here. If theymos is right, and he most certainly is, this basically means that Chinese miners do control Bitcoin, so my question set forth in the OP basically boils down to whether and to what degree the miners from China could trace Bitcoin transactions to the country of origin
When it gets Nasty, don't expect BTC to be left out of the Tariff war, by either side
Some might not have enough courage to accept that
In emergency you suggest here there could no choice, someone will implement it. It will be up to the users to switch to the new client.
where they got 5 independent PoW mining algorithms, it has been running for a long time, so it's possible. Some altcoins have a hybrid PoW/PoS. It has been done.