There are already bouncers to do that.
The advantage of the wordpress bouncer is to be able to ask for a captcha and to not completly block the IP.
The other advantage is if you are behind a proxy / loadbalancer and you can’t block directly on the front server. Then blocking on the firewall is not possible, but you can use the wordpress bouncer.
To make it simple.
- You want / can block on the firewall, use the firewall-bouncer.
- You cant / don’t want to block on the firewall, you want to ask for a captcha, use the wordpress bouncer.