Personally, I'm against "all strings should be f-strings" just because it would cause changes to source code that I don't find necessary. When Python 3.0 came

Personally, I'm against "all strings should be f-strings" just because it would cause changes to source code that I don't find necessary. When Python 3.0 came out, u"" prefix was abolished and every u-string had to be changed. That change was found later to be a mistake and was reverted (I'm not sure what python version reverted it, somewhere around 3.3 I think). This proposal reminds me of that: change that seemingly sound good at first, but is simply not worth it. Yes, there will be breaking changes and I'm not against them. I'm just against this one.