Im not sure how the heal waiting for a Bard to pass through it is a bad thing? Since most of the benefit is immediate it could be used like Indomitability and Assize instead of Earthly Star. You place it after damage on the group to restore health with the added benefit of anyone out of range being able to run into the field later and still get the heal which is more flexible than being outside of Earthlystar when it detonates. It seems more inclined to be useful for wandering dps than detrimental. Even if they dont see it for the first half of its duration they can still get a large reward for finally making it in. A DPS who has just revived can still catch the effect too.