Here is another issue related to WP/SP sites with a lot of users, mine has more than 105 000.
When trying to delete a User from WP Dashboard, there’s a SP feature listing the existing users so the posts for the deleted user can be re-attributed to someone else.
URL is like: wp-admin/users.php?action=delete&user=xxxx&_wpnonce=yyyy
This is rather problematic with a large user base, as the web browser doesn’t like loading a userlist so large. It actually works but need a couple of minutes of patience.
I’ve noticed the entry 0003948: Membership tools not scaling in your Bugtracker, I’m happy to see you are looking to better support sites with large user bases. Current issues such as the one in this post or this other one are especially annoying and I hope it can be quickly fixed.
Thank you.