ARMA medieval fencing masters, who study the real thing. Not the stats, the number crunching, the Great Shield debates, or the abstract hit point related simulation systems called chainmail or D&D. They do the real swordfighting, live.
And on this swordfighting lesson video the teacher (I'm not sure if it's John Clements, but could be) explains the difference between a longsword vs a side sword. The latter, he explains, is rather effective on the battlefield, but the former is much more effective in the street - vs. a single opponent.
That's because the reach of a longsword is greater, even if just a bit. And one hand is kept free, to parry with for example. So, the longsword is excellent to carry around "on the street", because you can quickly take down an opponent with the longer reach. But in the battlefield a side sword (broadsword?) is more useful, because you can create a swooshing barrier to keep enemies from all sides away from you.
I'm not too sure if the difference between a battlefield situation and a one to one situation is at all reflected in D&D (or other) game rules. I know of no example. But I figure it should be, or at least it would add to my enjoyment and feel for the game if that were the case.