Problem/Motivation
If we take a look at http://drupalcode.org/project/drupal.git/blob/refs/heads/8.x:/core/modul..., we can see that 90 LoC are needed for a method that is only 5 lines. I call that madness :)
Proposed resolution
Introduce a ControllerBase class that is ContainerAware and has the same helper methods as \Drupal.
Remaining tasks
Expand and properly word the definition of 'thin' controllers.
User interface changes
None.
API changes
None, just an API addition.
