It is typical in fiction. The hero dons his armor grabs a long sword and just goes swinging it at guys/orcs/goblins/(Insert foe here). Several problems: 1. Armor is not useless and a foe in even cloth armor will shrug off a sword slash. 2. If our hero has just a long sword and his foe is bringing a shield and a polearm, the hero is at a distinct disadvantage as the spearman is protected by the shield, likely has a helmet and has a 5 foot range advantage minimum with the polearm. 3. Long swords are sidearms in case your primary polearm breaks. It is not the first weapon of choice. The Romans got away with their way of war for so long because they had a large shield to bash people with and faced largely unarmored enemies who lacked discipline. As their foes started armoring up and getting disciplined, they began fielding spears more often. 4. Long swords are actually three weapons in one. The pommel doubles as a mace and the cross guard doubles as a warhammer. Fencing manuals from the 15th Century empathise using the cross guard and pommel against armored foes as seen in Halbschwert against Mordstreich in the Codex Wallerstein Plate 214. This would knock an armored opponent out and enable a killing blow when they were down though a visor or other gap. 5. Against unarmored opponents, half-blading as you thrust, adds substantial force to the thrust as opposed to thrusting with both hands on the handle and if you're strong enough, you can even thrust through chain mail with such a thrust. As a side note, the Mainz-type Gladius was specifically designed with thrusting through chain mail with a specialized tip for that purpose. It is also good at cutting and will take an unprotected arm off. So in summary, if your hero is packing a long sword, its a sidearm to a polearm. If he brings it out against armored foes, he is using the pommel and cross guard to knock his foe to the ground and if thrusting the blade, he will half-blade it. Anyone else want to add any pet peeves they notice in Fantasy/Pre-Modern Melee Combat stories that just rub you wrong and want to see fixed by authors writing in those types of settings for more believability.