Jumping in - we need this feature, too.
For example, Sales Rep A. is a veteran and therefore receives 70% of inbound leads. Rep B. is a rising star and should get 30% of inbound leads. If we distribute with the default even-split round robin, then we risk losing 20% of inbound leads AND set up Rep B. to fail.
HubSpot product/dev team, please understand that this is key to SaaS companies.