I'm pretty sure the same limitation that makes you get interrupted when a mob moves 3 feet, will also prevent this kind of thing from being easily added. They'd have to fix this problem first before they could let us move and cast. I'd love to have it, like back in 1.0, they made it where we could move. Maybe they can one day, I'd like it. But for some reason I think that them giving bards a skill to stand still, is kind of a way to keep other dps from caring that they can't move. And likely would indicate them not worrying about a feature like this.