This is a pain point for us as well. Due to restrictions on Teaming in Hubspot we assign multiple owners to a contact to ensure all relevant parties have access to the contact. Our sales people have started to view Owner Assignement notifications as spammy but do not with to disable them for fear of missing a good opportuntity. Having the ability to control assignment notifications, such as restricting the notification to the ‘Primary’ contact owner, will cut down on some of the noise relieve some headaches for our sales team.