Is registering a controller as a service still frowned upon in D8
From a Symfony docs discussion

fabpot commented


  @lsmith77 is right. I strongly believe that this is NOT a best practice. I don't recommend it at all. That's why it's not in the book and explained in a cookbook entry.


mahono commented 


  It would be nice to understand why what is (not) best practice. @fabpot: could you give some more info why you think so (or is there more information about that somewhere else?) To me most important is to learn best practices how to make my bundles customizable.


fabpot commented


  The DIC mostly helps manage "global" objects. Controllers are not global objects. Moreover, a controller should be as thin as possible. It's mainly the glue between your Model and the View/Templates. So, if you need to be able to customize then, it probably means that you need to refactor them and extract the business logic from them.


With that said, here's a blogpost arguing for controllers as services: http://pooteeweet.org/blog/1947