This thread is becoming a litany of things that annoy Scott P Jones rather than having a specific focus.
You keep saying that string performance has gotten worse with zero evidence, whereas I’ve shown benchmarks that are the same or better. At this point this just seems like FUD you’re putting out there because you disapprove of some of the changes. (Which perhaps not coincidentally revert a lot of changes you made a few years ago, as I’ve already pointed out.) Either provide some real benchmarks or please stop making baseless claims.
Regarding things being broken – yes, that’s what happens when you make breaking changes. Packages defining string types will have to adjust.