Well, there's a few other things wrong there: 1. Late Romans also used a longer sword called a Spatha, which was an evolution of the same design that replaced the Gladius. 2. The uniform equipment of the Roman army is much over-exaggerated. 3. Dude dieing of an infection days afterwards is not at all a battlefield consideration. Or even very probable, because they would keep on stabbing you until the point was moot. 4. Barbarians didn't use two-handed swords either, because... 5. Until the late Roman period nobody had the metallurgy or quality of metal ore required to make such a weapon. Nobody even had the choice, and when the Roman had the choice to make longer weapons, they did.