With a camera, your raw material is the scene, only. People working with the old film cameras could still do some tricks during film development and reproduction to improve the quality of photographs. But the important part of their work was in front of the real scene.
With Photoshop (and equivalent) you can do this and a lot more. Their raw material are files, not the scene.
My approach is to use this kind of software in a way equivalent to what was done by traditional film photographers : crop, white balance, luminosity and contrast. That means, I try to emulate the work of traditional photographers - my pleasure doing photography is doing just this.
I can accept to do more, but it shall be a justified exception, not the rule. Either way, I don't know how to handle these programs to do more than this. My computer run under Linux and the software I use are just gimp and RawStudio.
I think both approaches are valid, but they aren't the same kind of work.