Fill in custom values in a newly created document

In 2.12.07 it is possible to fill in some property values dynamically when creating a new document. For example, the current date can be automatically filled in by adding a property-path -> value mapping in the hippostd:modify property of the query template. However, this mechanism only supports a limited set of predefined variables, such as $name, $now, $holder.

What I was looking for for our project is to fill in the "title" property of a document with the label of the document. I can't use $name, because that is the node name of the document, and not the translated label. So maybe a new variable $translated-name (or smt similar) could be added to the set of predefined variables?

To go even further, I would like to have a mechanism where I can plugin my own variable resolver. For our project we might need this later to fill in custom user-related values.