@Snaedis I am glad to see that we agree that flexibility over the tag URL is preferable.
With regards to SEO and non-English characters in the URL, as usual it depends. Google can read both english and non-English URLs, so the page will certainly be indexed by Google. But what visitors and sometimes the “market” expects differs. As far as I know, in Japan it is best practice to use Japanese characters in the URL path, whereas in China it is best with English characters. In most European countries, website visitors expect to see URL with their own special characters (e.g. in German, French, Spanish, Portuguese, Danish) converted into english-characters-only URLs.
Anyway, if it is possible to have control over the URL, then the best of both worlds can be achieved.
