Tbf it was for mobility and defence., It just needs to be made so the fire and acid mechanics damage the operative no matter how or when they roll. Then its balanced If you say for example decide that the concealment roll needs changing and changing the format from active to passive mitigation then they would have the mitigation while being able to do damage while now they can't do damage while rolling. Also putting the mitigation elsewhere means they still have the roll to get away etc even without the concealment buff to it.