Replace core translation with this module.

This is already possible! You can switch to this mode on the settings page (admin/config/regional/symfony-translation). The differences are explained over there.

Ok nice, will check it out. Thanks for the quick reply ;-)

The module still has a dependency on the locale module though, since it falls back to it. Core and contrib all use locale for translations, so disabling it and only enabling Symfony Translation would mean that only custom strings defined in translation files would be translated. Correct me if I'm wrong, but that doesn't seem like a realistic situation to me.

Yeah I was looking into this, because of some issues we have regarding locale messing up config translations. In my opinion, core shouldn't redefine default config into the default language (if different from EN, but rather store all config in English (source) and use language overrides as translations. Now it just seems like a mess :-) I came across your module when looking into how Symfony does its translations and then wondered why drupal just doesn't do it that way... But I guess locale is too tangled up in core to really leave it out.