Eh. Honestly, so far Sonnet hasn't had any trouble with it. The thing is that every time it changes anything, it rewrites every line of code anyways just because I ask it "please give me the complete changed file(s) for easy copypasting."
The effort tradeoff is different for AIs than humans. Easy-to-understand-locally is more important than cheap-to-change, because it can do "read and check every line in the project" for like 20 cents. Making AIs code like humans is not playing to their strengths.
[0] https://github.com/Guesspage/guesspage.github.io/blob/master...