That would be amazing 
I’ve been getting a lot of questions this week along the lines of “how many of the forum users are active each month,” and have been looking for a way to get hold of that data.
EDIT: Though on second thought, are both versions of “active” just based on a user logging in to the site? Or would they need to also check for unique users logging in, rather than total logins? 
If MAU is simply the number of logged in users visiting the site, I guess that could just be pulled from the existing User Visits report (adding up monthly totals).