Well the thing with bard's is that the combo points are interchangable. For example if you were to put charges on a target with the sab soul, you then cant use those cp's with a bard' finishing skill.
Right now versus single mobs i just use ranger attacks + headshot, or if i need health i cadence + power chord + headshot.
Using just bard skills you wont be doing alot of dps, but if you combine it you can easily be doing alot of dps, up to the point where you're dps is equal or higher than straightforward dps.
The biggest dps loss if keeping your motifs up. But you can recover that because the bard can generate combo points really fast. Headshot to finish it. Do that 2 times and you're back to normal.
Solo"ing its a very intuitive soul, need healing? go cadence. No need for healing? nuke it down.