Suggestion:
Provide more customizable alerts.
What I would like is to be able to get a daily summary instead of just specifying the maximum no. of emails per hour because when my sites are under bruteforce attacks, I don't want to get a notification every hour informing me of the same.
So, maybe, you could provide time intervals for alerts as well - hourly, every 12 hours, every 24 hours etc..
P.S. Please update the Screenshots on the WP repository. They're of an older version.