I have an 04 F350 and I also feel the brakes were weak at best. I just changed the fronts to dimpled and slotted rotors with semi metalic pads. I havent towed with them yet but they did make a significant change to braking action.
There is someone around one of these sites that says the dimples and slots are not needed, I dont know for sure but I do say the braking action is better. My son put them his F150 at all 4 corners and really likes them much better and he no longer has the nasty brake dust on his wheels or scored rotors to look at. The set for the fronts was about $275 or so form one of the online business.