>But if history shows it's difficult to implement something without creating vulnerabilities, and there are alternatives which are less prone to mistakes, it should be retired and discouraged to be implemented.

>Also, CBC itself is not an actual problem, but CBC in TLS is authenticate-then-encrypt, which is how the vast majority of problems are created.

Oh definitely, GCM (or another AEAD cipher) is a much better choice - I wouldn't argue in favour of CBC in production TLS cipher suites. I just wanted to comment on the technical details of where padding oracle vulnerabilities actually arise.