Cap'n Kobold
Hero
Its basically a Longsword that does piercing only* damage.I've wanted to put an estoc on my weapon's table for a while, but I can't figure out exactly what stats to give it such that it has unique advantages. The problem would be even worse in 5e.
I generally use short sword stats for the later rapiers/sideswords as well.You make good points, though we disagree, I think, on what the DnD rapier is, in the evolution of weapons a modern person might call a rapier. IMO, what D'artagnon uses is a later rapier, closer to a small sword than the sturdier, quite long bladed weapon I've got on my wall. It would take quite a strong person to fight case with the rapier on my wall, while I've used blunted and tipped smaller blades more like the later "Dumas" weapon with very little muscle effort, because the are very light and balanced nearly at the guard.
Anyway, a few other points, in response to you and others:
Main gauche: precisely my issue, is that there is no benefit in 5e to a rapier wielder putting anything in their off hand, other than perhaps a shield, unless feats are in and hey take the dual wielding one. A simple, non thrown, Defensive (AC +1) dagger would be great. If the rapier is supposed to model D'artagnon's weapon, then it should be Light. But, as it is, the short sword models that blade better than the rapier does.
Longswords. They're long, not really finessable swords most commonly used with cutting effect*. Arming swords definitely have the capability to be used two-handed for a bit of extra oomph through the use of half-swording. Even viking swords can get some improvement out of using two hands with them; they're not as efficient at doing so than a longer-handled weapon, but I don't think that D&D combat is really granular enough to make the distinction.Also, which sword represents the "Viking sword", ie, the swords shaped like longswords that didn't have a haft long enough to dual wield? In 4e, they clumsily call it a broadsword and make it less accurate, but in 5e it just doesn't exist, outside of reflavoring he rapier or shortsword.
Heck, why not rename it arming sword? That vaguely covers a wide range of relatively light one handed swords.
*I houserule that weapons can deal the damage types suggested by their design. So most swords can deal either piercing or slashing damage, many warhammers can deal piercing damage etc.