Not so, Skyrim has two very clearly different types of bow. The early game, weak bows have a significant drop in the arrow's flight. Later bows, like glass, ebony or nordic, don't. (Though dragonbone may be an exception.)
It's not a continuum. Every bow is defined as either fast or slow, and all bows of the same type apply an identical trajectory and range to their arrows. (Yes, I've actually spent time testing this.)