If you have only one website with less forms the persistence structure of the form data is okay. But with more the one site and many languages, you will lost the overview about the stored form data.

It should be better if the form data is stored in the same structure like the page structure. So you can maintain the access to the stored form data. E.g. the editor for site-A and language de (in website below /site-a/de) has access to the form data in the same structure.

Furthermore the single form entries should be stored in date based notation and not only with a numeric name. See attached screenshot.