Does anyone else experience their transmission shifting into reverse uncomfortably hard while in low range? Mine shifts great in high, but 2 is pretty hard. Is this in part due to my low stall torque converter? Will installing a upgraded valve body make this worse?

Assuming your talking about going from Park to Reverse, try shifting from Park to Drive first then from Drive to Reverse.

Just a sign of a healthy tranny, a higher performance VB will go into gear quik but as you said a torque conv and idle speed will determine how hard it hits going in gear

What you are feeling is the torque multiplication of using low range. Ever notice how much more brake pedal pressure is required for low range? That works the same way.