We might have the same goals here. I had expected to be able to produce a dynamic report each week showing how many profiles, opt-ins, opt-in rate, new opt-ins, newly churned, churn rate, and # of users who met various other segmentation requirements - and to be able to show trend data about the growth of these stats over time. I learned that ACS does not enable any reporting at all for Profile table attributes - it can only report on campaign results. A workaround was to create "audiences" for any specific attribute you wanted counts for, such as # of subscribers, but then you would only see the counts for that 1 day and not know how many you previously had. As a result, I worked with my implementation team to create a Profile Reporting table where I had all of the stats I needed run in weekly workflows and fed into this table, so I can see how many and/or what various rates were each week over time. There is no graphic functionality on this table, so I then export to a Txt file and convert to a CSV for more detailed analysis.
I am lobbying Adobe's product team to add profile reporting, as I feel this is an important missing feature.