I have tested few times...
From my personal opinion without WM bard can atatin fair or more DPS + mobility.
With WM you can have massive burst with the combo "Raging Strikes" + "Hawk's Eye" + "Blood for Blood" + "Barrage" and followup by Empyreal Arrow.

I'm wonder what will happen if we can lower our GCB from Skill Speed & Cast Time from Spell Speed.
Could you imagine if we got castime less than 1sec and GCD less than 2sec... This could be Imba.