As a user, I want to edit existing activity feeds. I only see a delete function in the current iteration. This will allow customization of each activity feed.
As you had mentioned, the current interface allows you to add/delete activity feeds. This gives you the ability customize your feeds to show the information you care to distribute.
At this time, we do not have plans to make updates to the user experience (to allow editing) but we hope the workaround to delete/add feeds will help you to achieve the same goal.