• If I'm reading you correctly, henceforth code is available only under the MIT license (or your modified version thereof), not the CC BY-SA license. Why not retain the existing license, and add the MIT license? This would make life a lot easier for people copying posts from here. It's much easier to copy an article if the whole thing is under one license.

• Define, please, "code".

  This condition is met when a > 3.

Is that "code"? Is most of that sentece CC BY-SA, but those final characters MIT? Is this not a mess?

• If I edit someone's post to format their code properly, am I changing their license terms? Do I have legal permission to do that?

• If I'm reading you correctly, henceforth code is available only under the MIT license (or your modified version thereof), not the CC BY-SA license. Why not retain the existing license, and add the MIT license? This would make life a lot easier for people copying posts from here. It's much easier to copy an article if the whole thing is under one license.

• Define, please, "code".

  This condition is met when a > 3.

  Is that "code"? Is most of that sentence CC BY-SA, but those final characters MIT? Is this not a mess?

• If I edit someone's post to format their code properly, am I changing their license terms? Do I have legal permission to do that?