Rather than proposing complex mechanism, isn't it more practical to revive P2Pool (decentralized pool) and encourage miner to use decentralized pool?
the case censorship could be a problem eventually
If we're going to have large protocol changes anyway, wouldn't it make more sense to make transactions private by default (like Monero)? You can't censor what you can't see.
Monero transaction have bigger size and take more time to be confirmed, so i doubt it'll happen.
And how long do those 3 mining pool operators need to doublespend to destroy trust in BTC.
Less than ½ hour,
and if they are on an exchange or markets that lets them short BTC or short companies that own BTC,
they could become insanely rich in a single day, and no longer need to run a mining pool.
1. 0.5 hours would be difficult since some exchange require 6 confirmation.
2. Huge withdraw usually is reviewed manually or checked more thoroughly by the system.
3. Unless they swap BTC for decentralized altcoin, they face risk their fiat or altcoin frozen or reversed.
4. They'll be arrested unless they could secure cooperation with various corrupt government worker.
5. etc.