Daggermaster isnt broken with Rogues. It's broken with multiclassing especially with the wraith weapon offhand and a viscious main hand. I had an avenger that at level 15 would only would hit for 17 average damage at will and then blow up for 150-200 30% of the time.
Thats what makes it good. Giving not only the class designed for a good option, but versatility for other classes as well.
It gives good bonuses most of the time. Too many paragon classes give "resist 5 when a dragon is doing cartwheels and The Fury is playing a fiddle" type situations.