The problem with that combo is that concentration is a minor stat... so you'll get the same amount as celestial. So it becomes a question of how much that extra condition damage is worth compared to power + precision + ferocity (and short bow has a decent power scaling). Might still win out, I have no idea, but the gap will likely be small. On the bright side, that means not having to deal with the toughness headache.
Feels like they tailored the thing for Harbinger more than anything else.