This proposal does not make sense, since sorting non-ASCII strings is locale dependent, so there can't exist a `sort_by_utf` method. The `sort_alphabetical` gem is broken in this regard, as well:
```irb
$ irb -rsort_alphabetical
irb(main):001:0> ["i", "ı"].sort_alphabetical
=> ["i", "ı"]
irb(main):002:0> ["i", "ı", "ü", "u"].sort_alphabetical
=> ["i", "u", "ü", "ı"]
```
As a general point, string literals are not going to be frozen any time soon, and there will always be an option to disable it even when string literals are frozen by default. So, IMO, this is not a valid argument for adding features to Ruby.
Ufuk Kayserilioglu