Yeah this is just a short suggestion i personally find cool, the ability to fight with 1 hand sword without being punished. in almost every game you can use 1 hand weapons, but that is always either dual-wield or sword and board fighting, i would like to be able to fight with a 1 hand sword for more speed. like using a rapier not about slashing as much as possible but about agility and freedom of movement.
I mean there’s a reason that in history not many people ever dual wield. Dual weilding makes the user a bit more clumsy and each sword is less powerful for obvious reasons. I definitely want single sword fighting to be balanced in with dual / sword and sheild / long range. The more playstyles the better.
So basically a two hand sword let’s you parry, two one hand swords adds to strength, and a single one hand sword gives a dex boost. Or something like that just to create a smart balance so that your choice of weapon is effective in its own right.
Rapiers could have a chance to ignore armor. You could stab trough gaps in armors couldn’t you? 
yes and no. depends on the armor, but if going by logic they usually have plate armor and then a chain vest under, so it would be near impossible.
Zouls is right. Armoured knights generally didn’t fight each other, they just waded through the unarmored peasantry. It was more typical for knights to be captured and ransomed than accidentally killed as plate was near impervious to weapons of the day.
That said, who doesn’t love the idea of totally outlandish weapons beating all the odds? Give me a scantily clad, rapier wielding avatar any day 
Swashbuckler achetype ahoy.
