The only problem with HST pedals whether one or two is the location. Hardly no way to use the brakes and the HST pedals at the same time (legs crossed over one another-one to work the brake and one on the HST pedal is a PIA). I do like the treadle pedal on my
B26 much better than the 2 pedal system on my BIL's New Holland which creeps a bit when you let off the go pedal so it confuses me as to which pedal I am pressing. I almost ran it into a pond once when it keep going forward and I stomped on the other pedal which really made it go forward. I guess I could do better if I drove it for a length of time, but I much prefer my treadle pedal and if it was on the left side it would be perfect. I do seem to recall some post here that said some models of tractors now put the brakes on the left or was it pedals on the left. Either of which would work after some getting used to the location just as long as the steering brakes and HST pedals aren't on the same side. Also something to check out, I wouldn't buy a tractor that didn't have steering brakes (dual brakes left and right side) even though lots of folks never use them, I find them necessary on a tractor especially in the mud. Steering brakes also when used diligently allow for shorter turning without having the front wheels tearing up the grass or digging a trench in soft soil.
As for hard to push on the rear treadle pedal, it shouldn't be much different forward or reverse. Have the dealer check out why it is so hard to push for backward movement. Might just need a bit of grease on the pedal mount. Check out any other model to see if they all seem harder to you.