I’ve got nothing left to contribute, but I am surprised by your stance. I expect urlize to sanitize a URL by encoding it.
I am not discounting your experience, but it is not a foregone conclusion that no one wants URL encoding, or that people look down on it as unprofessional. Some of the largest sites in the world handle URLs in this manner (such as Wikipedia).
I see conflict in the docs between urlize and the explicit instructions around preserveTaxonomyNames, but I do not agree urlize is not working as expected. 
I was about to suggest looking in the GitHub issues, when I found two that concern you:
- Special characters in taxonomy and slugs - explains why some languages require accents and encoding to work properly
- Remove Accented Characters from URLs - suggested the undocumented config option:
removePathAccents = true
So I suggest you try that, and if it works, add it to the configuration doc.