I'm all for using less pins for hunting especially with the faster bows.
My setup only shoots about 220 fps so I have some drop, but the difference in point of impact between my 20 yd pin and any point out to 20 yards is less than 3", assuming I'm not shiverring too bad when I let go of the string.
I like to have a second pin on my hunting sight though.
I can set it one of 2 ways.
I either set it to be dead-on at my max shooting distance, say 35 or 40 yards, so I can prorate the distance between the pins and get a more exact aiming point on an animal that is between 20 yards and my max range.
The other way I like to use it is to set the pin so that the vertical distance between the pins is equal to the vertical distance between a deer's chest adn back when he's at my max range. That way, if he looks too small in the sight, I know he's too far away.