There has come an argument in my group that i would like people's opinion on. One of the newer players in our group is arguing that swashbuckler's finesse will allow him to use his dexterity modifier instead of his strength with any piercing weapon he picks up.
As best as i understand it, the argument is as follows:
Swashbuckler Finesse (Ex): At 1st level, a swashbuckler gains the benefits of the Weapon Finesse feat with light or one-handed piercing melee weapons, and she can use her Charisma score in place of Intelligence as a prerequisite for combat feats. This ability counts as having the Weapon Finesse feat for purposes of meeting feat prerequisites.
It cruxes on the definition of 'With' which basically means, paraphrasing: To add to.
Now the argument is that as long as the weapon is piercing, and because it says 'Benefits of the Weapon Finesse' Feat he can apply the benefits of weapon finesse even to weapons it would not be normally applied to, as long as they are a 'one handed piercing weapon'. This is because the BENEFIT of the feat is applied, rather then the feat, and the with's 'add to' means the benefit is added to apply to other piercing weapons. He is doing this in conjunction with Slashing Grace to make a... he never mentioned, ever the weapon he is using. I assume its a scimitar or something.
The counter argument is that the feat is indeed applied, but because it's effects only apply for light weapons and weapons which specifically say they can be used with weapon finesse.
The argument came about because the swashbuckler is consistently doing more damage then the strength based brawler in the party, and we put the rules he was using under an actual bit of scrutiny.
A developer's comment would be most useful, but we would like the inter net's opinion in a logical sort of statement.