Cap'n Kobold
Hero
Force, yes. But "brute force" implies a lack of technique and control, which is not the case. The proficiency bonus is the same whether the weapon uses grace and balance or athleticism and power.Right, but using strength to use a weapon implies brute force.
Even a weapon as sturdy as a longsword isn't going to shear through solid armour. But a more powerful person is able to change the momentum of a blade faster: adjusting direction mid-swing to avoid an opponent's parry or going from guard to effective attack faster and with less warning.The reason a short sword or dagger is finesse is because a dexterous person could use such a weapon to aim for gaps in armor and weak points with care, while a strong person could just ram it through your armor.
Big, probably, but bear in mind that in 5e, Strength is athleticism and ability to generate force. Bruce Lee is a good example of a high-str character for example. (And high Dex. And probably decent Con and Cha scores as well).I mean, we've got to keep in mind that in a world where a strength of ten represents average, a strength of 20 is a giant hulking person.
A real rapier requires somewhat more strength to use effectively than a longsword: the point is controlled by the muscles of the hand and forearm. It takes quite a lot of power to move the tip of something that long rapidly and with control - whereas the longsword's handle allows two hands to exert a much higher leverage using less force. A less athletic person can compensate by using a smaller, lighter rapier, but they then lose out offensively and defensively in terms of reach.So if we're going by that understanding, a strong person should be able to use a rapier (a finesse weapon) with equal deadliness as a nimble person. It ought to be a sturdy enough weapon to pierce at least weaker spots in armor by the force of a strong hand. Actually the only weapon in the PHB that's listed as finesse that I can't really imagine working in such a way is the whip, which requires some level of dexterous technique to work as a weapon at all and brute force wouldn't really help you.