Having access to 10 cross-class abilities is very nice... however most-jobs get most of the class skills they would use without this.
I know that Marauder can support higher damage than War... and while we don't know the exact changes, I suspect that Archer will be able to do comparative/more than Bard.

Given actions like Sword/Shield Oath and Defiance it isn't out of the question for a enmity-suppression toggle skill that works for the tank classes if they are going to branch into DPS roles. Additional roles will take time to balance out with what already exists so be prepared that if/when more classes are added (or level cap is raised) that there will be a lot of class-tuning going on.