I am sure your already lined up with suggestions from the ground to your neck, and I am glad you accept suggestions. In phpbb as a security measure, which I like, a user can have it set up in their user panel that when they immediately log-in an email is sent to them with date and time of their log-in with the ip address. This was and still is a great mod for phpbb. I use a plugin as well called wp-united and this is how I noticed the lack of this security feature and 0 plugins that offer it which once again is a security feature for not only us as admin's but also for the user themselves.
It almost sounds like it could be something that your mod could handle and would fit the bill still in your plug-ins theme as security. Allowing the registered user to partake in their own security of their information as well. The Phpbb Mod is called Alert for Login and I only offer it to show a bit more of what I am talking about.
Hope you may take interest in what I at least find valuable in phpbb and the lack of here in wordpress.