Fair enough. But I am also a professional TD, and I like sets. And I say that from years of experience of my own - although my professional career is yet young.
It's true that character sets are considered an input, but in most cases you can have your cake and eat it too.
Want to put something in the character set, and also have the option to constrain them on a per-shot basis? Put a group above the character set item, and allow constraints on the group. Works even better for IK; like each IK target can move in its own constrainable space.
Then if you want to make the rig more robust, you can put a second group above the constrainable group, which -is- in the character set.
Then, at any time you can bake your top-level group onto the constrainable one, and voila! All of the animation is now effectively within the structure of the character set; free to move and copy as need be. And the constraints are still active, still ready for another round of tweaking!
I like character sets for precisely the same reason you hate them: they define the character in a precise and enduring way, such that he never becomes totally entangled with one particular scene or another. It forces organization. It also tends to encourage you to take the time you would spend making patch fixes, and spend that time making improvements to the master rig instead. Thus, over time your rig becomes increasingly robust, accumulating improvements, and your rigging time is not siphoned away making expendable structures with no enduring benefit.
So. I can see the validity of your perspective; it does take a certain amount of commitment to build and maintain a rig which enjoys the advantages of character sets, without sacrificing flexibility, and perhaps that commitment is not worth making in situations where the character is not intended for sustained reuse... but I also believe my own position is entirely reasonable: a robust rig will always pay off in the long run, given enough animation time. A rig which sets up clear conventions and adheres to them is also easier to share with other animators. And you don't get into the situation of having to do the same pitch fixes repeatedly.
Trax, I won't defend. My own experiences with it have been mixed. But I haven't given up on it. I still believe that there is a place for it, and that I will eventually encounter that place and be glad it exists. Time will tell.