Translations is something blogger may not be interested to - indeed when talking about business you want translations to be easy.
When installing WordPress you're asked for languages but this is just for the interface. Location shouldn't be "optional". It is something any CMS today consider at it first (eg ps, drupal etc..)
Translated content shouldn't be a duplicate post (as done by wpml). This is stressful for database that will force to search related ids by language.
For example the "post_content" column should be in a pivot table that contains the language id. When doing "get_the_content" it will take the content per language and so on.