I was just quickly thinking if there would be any ways to possibly let players to use one-handed weapons without a shield with some kind of a bonus. I mean in a way that you really don't use a rapier with a shield when fencing and so on.
It doesn't have to be anything which would increase the damage, but rather have like a feat, enhancement or even a prestige (Duelist/swashbuckler prestige for fighter?)
http://dndtools.eu/classes/swashbuckler/ is the class, but could be implemented into Fighter prestige.
Would love to see that one-handed fighting would get some kind of love, too.