More than KYC, regulatory capture in general is the greatest unaddressed risk. Capture of exchanges, pools operators, and hashpower providers. Forced doxxing of users. Forcing pools to only include transactions where sender and receiver are both doxxed. Forcing hashpower providers to only send their hashes to the compliant pools.

If the majority of the hashpower is caught up in this, they can not only exclude non-compliant transactions, but can also orphan valid blocks added to the chain by non-compliant nodes in unregulated jurisdictions.