Steelstar and Cordovan do an in-depth preview of the Swashbuckler tree and the Single Weapon Fighting feats. It’s a pretty long video but it’s definitely worth watching.
It answers the questions I had on how single one handed weapons could compete with two weapons or two handed fighting. Single Weapon Fighting feats help by being able to use up to twice your ability bonus to damage on your single weapon. The Swashbuckling bard tree aids by helping you critically hit a lot more.
I think the new Bard Enhancements are going to be very worth splashing into or even to go full on Swashbuckler.