Sometimes action functions in the controller class can become huge and nasty, with many-many lines of code to simply control the flow of data from the Model to the View. At some point these huge functions completely lose track of the basic principles of good code, i.e. only doing one thing, being small, readable and manageable etc.
Would it be considered good practice to break these huge action functions into smaller private functions in the controller class or should the need of such optimization mean we should rather add them in the model?
I would vote for having the smaller functions as private in the controller so that they are relative to the action, but I have heard arguments that the controller should preferably be simple while the model can get huge and clumpy; and was just wondering which one would be the most preferred method.