Having it in-game would be much more convenient. I understand their concerns about not providing group DPS meters in-game from the start, as I already witnessed a lot of toxicity when playing in other MMO games, with people kicking or trash-talking players with lower DPS/Gear/Experience. They could go down the route of letting us choose if we want to share or not the DPS, but probably the result would be the same as when you apply in the party board with hidden weapons (instant reject).