Don't you think that people would think twice before going to war again following a brutal sword battle? When someone kills 10 people with a drone they are detached from the action of killing, they are less likely to protest the war. I'm aware this will never happen, however. It's practically impossible.No. It would would become fetid, horrible even. Guns kill fast and even if they gut-shot, faster then dying of infection of medieval warfare.
Now don't get me wrong -- I miss swords; I consider them to be graceful weapons of war and probably one of the classier eras of warfare. But the war and the conditions that followed back then never warranted going back to them unless in certain situations (close combat). Even then the wounds of the infected could fester and kill you. Medicine was limited. Even if medicine and science are better, I don't see the weapons reverting backwards. The newer era was too etched on guns from a young age. The eras have shifted; and unless futuristic swords are made (plasma beams, light sabers, what have you) there's no chance for it, sadly.
Plus stacking that many bodies in close vicinity in a battlefield friendly fire even takes effect. That's why wars are fought in squads and groups and and at range. The world had it's melee phase; now we're stuck in the gunfire phase.
It is an arms race. Be the fastest to create a weapon that will get you the advantage. Sadly, sword usage no longer gives you a real advantage.