There are no brake enhancements that I am aware of. However you didn't mention what year motorhomes you're looking at. If they are more than a couple years old it could be that they have water in the brake fluid. Ford recommends flushing the brake system every 2 years.
Also there's a world of difference in the feel of the brake pedal between the older series chassis with the 2 valve per cylinder engines and the newer series with the 3 valve per cylinder engines. The older ones have a softer pedal feel much like a car. The newer ones require more pedal pressure.
In addition there are 2 different power assists depending on the size of the chassis. The lighter 16,000 lb. and 18,000 lb. chassis use a hydro boost system with a 8.19:1 boost ratio. The heavier chassis (20,500 lb. 22,000 lb. 24,000 lb. and 26,000 lb.) use a Hydromax system with a 21.1:1 boost ratio
When we went from our 2001 motorhome to our 2103 motorhome (both on the Ford F53 chassis) we noticed a difference in the amount of pressure needed on the pedal to stop the motorhome. The older one took much less pressure. However after a few thousand miles of driving we are now used to the amount of pedal pressure needed on the new motorhome.