It's not that much better: it's an average of 1 damage per attack, which works out to 1-2 damage per round depending on whether you have a better use for your bonus action or not. It's also +1 AC though, and that's not nothing.@Gladius that's what im wondering, im having a difficult time determining if wielding 2 raipers is much better then 2 shortswords. If there isn't much difference (average of 2 damage) then what feat would be good for a swashbuckler, I was debating Lucky .
If you were weighing the benefits of an actual ability score increase, there's no way I'd take Dual Wielder before maxing out Dex. With +2 Dex, you'd get +1 to hit, +1 damage, and +1 AC. The +1 to hit is definitely better than the possible +1 more damage from the bonus attack.