The golden features in Drupal is the fact that it is a Content Centric CMS. As time goes by, while dealing with websites that are bigger, more complex and more advanced, it appears more and more that reality is in fact: a Drupal database Content Centric CMS.
As the Web is going more and more complex and interconnected, it starts to appear as a limitation. Ten years ago, we started to build bigger and more complex websites: Drupal 7 was just great for that. From now on, RSS ans Schema are not enough: API web is the key word. And migrating data is always a project in the project, a bigger risk for planning and money.
From our point of view, we should stop migrating data, and start plugging it. That's it.