Which of the two Thief dagger classes now feels better to play?

It's still a good indication of damage. If one class does 50% more damage of another class, it pretty much means given equal gearing the first class will always hit harder unless the person is playing badly. The %s of DB and Shadowers were much closer, but Shadowers still gave the impression they were buffed enough that if you give both classes roughly the same gear the Shadower will win out in the long run. But again I got fellow Dual Bladers (some who also played Shadowers) prove me that Dual Blades are still better.

Shadowers use different attack combos at different stages of funding, which means as funding increases, %ps decreases. Dual Bladers, as far as I know, use the same combo for all levels of funding. DBs also have an advantage where ranges are concerned, not to mention the secondary weapon.
Anyways, I'm just saying that I'm hesitant to compare two classes' damage based on %ps.