My concerns are that witnesses can blacklist some users and block outgoing transactions. In this case, most users will not be affected and will not have the motivation to change witnesses.
For example some guy will open SilkRoad and accept balls. Witnesses will decide to block all outgoing transactions from the seen addresses. Most of users will not be affected and SilkRoad users will not be protected from witnesses attack.
Another example: witnesses can block outgoing transactions from the whale address to prevent the dump.
Another example: witnesses can block outgoing transactions for all transactions over $10k. Users will need to pass a KYC, fill in the declaration, indicate the origin of the money for making such transactions.
hmm maybe this is why Byterbal integrate all this KYC solutions? .  Byterbal is Putin's answer to Satoshi?