Because I have built and flown the Dirty Birdy the thought of using the torque rods would never even cross my mind. It's a big precision plane that will travel at some pretty fast speeds and you could get some control flex with the system.
Gene-
I think the flex issue is related to a few things- but not to the torque rod assembly.
I do not believe plastic film coverings offer the rigid finish. Finishing with fiberglass or fabric/dope I believe helps fix this... as well as building up an aileron from gluing two sticks together and sanding to the airfoil. Sheeted foam would be an even better option.
I don't want the servo arm, push rod, and control horn hanging out in the wind- not that it will effect a whole lot, I just don't want it in this case.
Truth be told, in a classic pattern application,
I believe the torque rod makes more sense. But that is just me and I am really not that important in the history of model aviation, so it can only be taken with a grain of salt anyhow.
tailskid-
I agree with your assessment. It can interfere with internal hardware if the install is not properly pre-planned.
Top_Gunn-
I am assuming a proper application within my reasoning. You are correct that there comes a point where the application just will not make sence... especially in giant scale and jet aircraft.
Brian