The were many composite bows through the Ages, among the most remarkable were the ones made the Turks, and the Hun. They went beyond recurve, they were so curved that they had the heart shape that The King was refurring to. These bows were a composite of Wood, Bone, and Sinew (from horses I believe). The Turkish bow was somewhat better, coming from a later period and was essentially a refinement of the Huns composite. The Turkish bow used less bone, and a stronger and faster whipping bow.
Yew is a strong wood, but lacks speed, that is why it's mainly used in long bows, relying on it's length generate it's whipping speed. The Native's of the NW US used Yew Longbow with a sinew back, they were some what shorter therefore lack the range and force that the English Longbow had.
In Mass combat, the longbow shouldn't lose it's ap with range, the general practice was to shoot in high arcs allowing gravity to pull the arrows down onto the unit at about the same force that the arrow had as it left the bow.
Has anyone considered armor piercing arrows? While not being mentioned directly in the stories, there is no reason why they shouldn't exist, considering that they were invented shortly after plate armors arrived on the battlefield.