|Art by Jason Engle|
The main reason I adopted this philosophy is because of the class bloat that developed during the life of the 3.5 edition of Dungeons & Dragons. Occasionally, Wizards of the Coast would release a new supplement that presented a new base class who's shtick could already be handled by another base class or the right selection of feats/skills/spells. You'd also see classes that had rather niche concepts that honestly better fit a prestige class instead of a full base class.
Now, with that philosophy in mind, I really think Pathfinder would benefit from a Swashbuckler-like base class. The idea of an Errol Flynn-like character who focuses more on grace, speed, and flare instead of brute force and high stamina is an incredibly iconic in fantasy literature and definitely has enough meat to it to fill out a 20-level base class.
Secondly, there really isn't a good option for building a character who wears very little to no armor, doesn't use a shield, and fights with only a one-handed weapon. You can attempt to build it with a fighter, but it would kind of make the Armor Training ability pointless and you'd have a horrible Reflex save bonus. You can try and build the character with the rogue, but you'd be stuck with a lot of unwanted trap-themed character abilities and the lower amount of hp and base attack bonus would hinder your fighting capabilities. Also, rogues are horrible at fighting an opponent one at a time, which is what swashbucklers should be great at. You can fake your way through it by multiclassing and archetypes and the Duelist prestige class, but you wouldn't be able to play the character you want from the beginning or you might still be stuck with abilities that don't fit your concept.
So, if we were to sit down and create a Swashbuckler class, what abilities would it have? Well, it would obviously have a good base attack bonus progression and the good hit die that comes with it, a good Reflex save progression to represent the class's focus on agility and grace, a decent amount of skill points and class skills that mirror the class' acrobatic and social capabilities, an ability or two that would help off-set the negatives entailed in wearing light to no armor and not being able to carry a shield, help enhance its ability to fight with a light or one-handed weapon, and a few abilities that would allow it to recreate some of the daring feats seen in the old Errol Flynn movies.
Now, if I was going to sit down and build this class from the ground up, I think I'd take a few of the abilities from the Duelist prestige class and throw them into the mix (specifically Canny Defense and Precise Strike). Also, after giving the swashbuckler archetype for the Gunslinger class over at Tower of the Lonely GM, I'd also throw in a Grit and Deeds-like mechanic into the mix to allow for those Flynn-like acrobatics. I'd also probably throw in the Evasion and Uncanny Dodge abilities as well because they fit the class' concept.
So, what do you think? Do you think Pathfinder needs a Swashbuckler-like class? If you were going to design it, how would you?