You don't always have to take just plain "deal Xd6 damage and thats it" powers. The rogue actually has quite a few powers which focus on moving about quickly and such.
In fact, I don't really know what you are looking for in a swashbuckler. When I think of one, I think of a fighter who uses finesse and charisma to trick and defeat his foes. Much like Elan likes to think he does in the comics.
The rogue in 4e has a whole array of abilities which complement this.