Assign roles to the members in the channels
It would be helpful to assign roles to the people in the channels, e.g. product owner, observer, ect.(differentiate between acitve and passive user per team or channel). This would avoid everyone in each team getting a notification when something is posted there. Instead, only those people who are owners and actively work on the topic will receive a notification.
We also need some sort of 'observer' or 'moderator' role. We are a school and heads of subject departments want to be shared owners of several classes, but do not want to be active participants. I could imaging in the business world, a department manager may want such an 'observer' role. If someone is an observer/manager/moderator, they would be able to control the number of notifications they get to reduce the amount of noise these can create. Also as they may belong to a large number of teams, they do not want to have to do this on a team-by-team and channel-by-channel basis.