There's a reason we didn't implement that.
First of all, not all exception records are kept in the database. Older records are removed automatically, per the plugin's settings, to avoid filling up your database tables. Even a single day's result would be inaccurate if you are under attack.
Moreover, not all blocks are (or should be) logged. When a repeat offender is detected their IP is blocked. When the retry to access your site they are blocked and no event is recorded. This lowers the number of attacks recorded and it's exactly what you are striving for. You want to catch repeat offenders fast and block them. If you were to start recording blocked IPs you are performing a Denial of Service on your site which is counterproductive at best.
Then again, what is "the last day"? Is it midnight to midnight? Is it defined by working hours? Is weekend a singe day? Whose midnight (your midnight in the UK and mine in Cyprus are two very different absolute times)?
Also, how is that sent? Well, obviously by email, but how is that email generated? Do you set up a CRON job? Do you use a plugin and hope that there's enough traffic around the time of the day you roughly expect the report to be generated?
Finally, such a metric is utter nonsense. I would rather see ZERO attacks in my WAF log. Why? Because that means that my server administrators are doing their job properly, catching most attacks either at the OS level (e.g. iptables) or at the web server level (e.g. mod_security2 with a carefully groomed rule set). By the time a potentially malicious request has reached my web application I know that the server defenses have failed and I'm down on my last line of defense (or dealing with a false positive or an emerging threat). If I see my last line of defense being bombarded, day in and day out, especially with low priority attacks which are easily filtered out at the web server level, I know that I am on a low quality host.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!