I think what @chirlu means by "English MusicBrainz" is "a MusicBrainz which serves only English-speaking users and presents only the content those users expect". I agree that "MusicBrainz is international", and delivering only content the English-speaking user expects is an unacceptable retreat.
However, a good way for MusicBrainz to be international is to serve each user in the language they prefer, and generating the content which that user expects. That means the user interface must be translated, of course, and it's great to see that work under way.
But also, all the human-readable data in MusicBrainz must be translated. For example, MB stores machine-readable data about an Artist, including an MBID 9ddd7abc-9e1b-471d-8031-583bc6bc8be9. MB also stores text of a human-readable name, "Чайковский". MusicBrainz does not store the data that this text is of a name in the Russian-language characters and conventions, but it should. MusicBrainz does not have a way to store a translation of that name into English-language characters and conventions, e.g. "Tchaikovsky", but it should. It should also have a way to store translations of that name into German-language conventions, "Tschaikowski", and Korean-language, "차이콥스키". It should also have a way of transcribing text from any language to any other language, for the case where no translation is explicitly stored in the database.
MusicBrainz does have a hack for English-language translations of non-Latin-script data: the sortname. That works only because the convention is for the sortname to be expressed according to English-laguage characters and conventions. It doesn't give the Korean-speaking MusicBrainz user the translation they should expect. Nor, for that matter, does it give correct sorting to anyone but the English-speaking user.
I think making MusicBrainz able to serve each user in the language they prefer is a monumental project. It will require a big database schema change, so that every bit of translatable data is tagged with a language code, and can be joined by translations of that data. It will require functionality to take the target language into account when retrieving data, to look for translations, and to do transliteration when no translation is available. And, it will require the UI localisation already under way. I think it would be a fantastic project to work on.
In the meantime, while I don't want "Чайковский" to be the name in the English-language metadata for my own music files, I agree that it's the best choice for an international database with its present structure.