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.

I guess what truly creates a "better" class is the feeling that your moves are not only powerful, but shiney and chain together very well. Personally I've never felt a shadower's moves play off of each other very well, and usually you're stuck using just one move over and over again.In comparison with a dual blade who can use several different moves, one after the other with booster, a properly eliminate a group of monsters.
But if you sit down and compare a pair of classes number per number looking at it strictly from a DPS perspective, the idea of a class being "fluid" is thrown out the window.