How to have required fields on the target content type populated?

Problem/Motivation

When a node gets converted to a content type which has more required fields than the source one, those "new" fields will be empty.

Proposed resolution

There should be a way to "force" the user to populate those fields during conversion. For example, have a second step of the node conversion form with those "new" required fields.

Remaining tasks

User interface changes

API changes

Data model changes