Looking at the prestige, I can understand why some people are disappointed in how it's being handled.
I'll start with the Core Abilities: Spell Power is inherently added whether the character is swashbuckling or not,
Level 1: Swift Strikes: 1% Dodge, is pretty much useless at that level, and unless wearing robes/outfits it will probably end up being useless as well without it being %1 Dodge and Cap.
Shield Proficiency: Buckler
Level 3: Swashbuckling: It's nice that you guys made it a stance, however does it work with other stances? Defensive Stance, etc? Weapon Finesse
Also, since there are no cutlass in the game, can we substitute it for scimitars?
dagger, handaxe, throwing dagger and short sword: +2 threat range
Light Mace, Sickle, Dart, Throwing Axe, Throwing Hammer: +2 Threat Range, +1 Multiplier
lightpick: +1 threat range
kukri, rapier: +1 multiplier
I did take out shuriken, that's what Drow are for.
Level 6: +5 Sonic Spell Power
Level 12: +5 Sonic Spell Power
Level 18: +10 Sonic Spell Power
Capstone: +10 Sonic Spell Power
Blow by Blow: Don't make the cool down too long.
Aqua Vitae: Is pretty much a joke with Self healing characters.
Swashbuckling Style: Should have something for two handed fighting as well.
Swashbuckling Style II: Slap in the face stun might last 2-3 seconds instead since it has a save.
Thread the Needle: Is kinda of a joke, since it only works while in Precision Stance
Those are some suggested changes, but still the prestige seems a little weak even after those changes.