Controller File Size/Length

2000 - 3000 lines is still Okay. I think even 10,000 lines of source code is still okay as long as it applies good algorithm and MVC rule and make it the code easy to read, such as pay attention about indentations.
In addition, especially for speed, the first part to execute in Controller is construct method, if not so many libraries or class load there, for example Models, let's say under 5 models not load there, it is still okay, i think.