I want to make clear that I like, and recommend, this build. It's a real nice pure warchanter build. Pure or mixed builds, however, can bring something to a raid.
I'll agree a pure bard is a safe bet and my personal favorite type of bard. I'll also agree many that splash don't have a clue, or the wrong clue, why they splashed. For those who know why they trained in multiple classes however, and know how to take advantage of said benefits, should be highly effective. There is no such thing as a "best" bard build. Its the driver, not the car, that makes the "better bard."