This is the threshold in question

Additionally, when the balancer threshold is set to 1, there is no longer a need for the aggressiveBalancerHint.

Background:
Because of the way how thresholds are computed, it is possible that the balancer won't take action after a single new shard is added to the cluster. Lowering the threshold can help in this scenario. We should also remove the part where we take the ceiling of the threshold and keep the fractional component when comparing thresholds in order to not be overly aggressive.