I think canister takedowns should be a rare occurence and only be used to remove canister with: malicious code that damages the IC, CP and illegal markets(drugs, weapons, etc…), everything else should be filtered by boundary nodes as proposed by Dfinity: Path forward on leveraging boundary nodes for content filtering
Immutability is one of the selling points for decentralized systems, but currently the IC is pretty lacking in this aspect in my opinion, considering there is the potential of lots of value being locked in the IC with upcoming DeFi and direct integrations, we should guarantee canisters can’t be taken down easily.