Dan was right again - BitShares was a necessary compromise between immutability and flexability

Once again, Dan's theory about immutability vs flexible forkability is finally being looked at by the crypto masses. This is why BitShares has the ability to fork at will, but that means that it is not highly immutable as a blockchain where no node has a copy of the entire chain (for instance WBB v5 design).

http://www.coindesk.com/immutability-extraordinary-goals-blockchain-industry/

How can we quantify an immutability coefficient for a given chain such that a low score would be shared by Ethereum and Ripple, while higher scores would be associated with chains that are difficult to fork.