The musket had a longer range true, but the likelyhood of hitting was so slim. Example, after the Battle of Cannae, General De Saxe inspected the battle field, of the long/medium ranged volly fire 50 men out of the 40,000 plus were killed. The rounded bullet of the musket can take much of the blame for this. Japanesse muskets were not the cream of the crop. European traders would often use inferior material in creation. The Arquebusie was even worse, often exploding in the hand of it's wielder (also due in part to an inferior purchase.)
as for skirmishers, history would bring a new form of "skirmisher." enter warfare of the 2nd world war and on.