"There is no single obviously correct solution to these issues. Instead, each decision was sort of weird and contingent and reversible: not the immutable code of the blockchain, but just humans sitting around and trying to figure out which approach would cause the fewest complaints. In that, it's a bit like the Dole settlement process -- only instead of a neutral judge making decisions based on written contracts and established precedent, it's the people running each exchange making their own judgment calls."
This is what I'm always repeating about blockchains: they're very valuable if and only if you cannot use the protection of contracts and laws when making a transation - for example because you're doing something illegal. In Every. Other. Case. systems based on trust, contracts and law (such as the banking system for example) are more efficient.
It doesn't mean that there isn't room for improving existing systems, just this is probably best done with regular servers and databases rather than a blockchain.