I hear what you're saying but layer7 DDOS attacks are a mouth breather variety. Need to burn them with fire, network level. Because it's not just HTTP it's the whole network stack you'll be chasing around with wacky-wavy hands (just incase).
You used enough unknown-to-me idiom in that that I actually have no idea what you meant. ("wacky-wave hands"? "mouth breather variety"?)
Sorry for the flippancy, what I meant was it's just 1 application layer protocol (HTTP) amongst the multitude you could potentially be serving. Trying to fix for that one service means nothing, big picture, to people who know how to suppress a network, broad spectrum. Think ICMP, UDP, TCP, routing protocols (BGP if they're feeling sassy), everything that happens on the wire and in the kernel and through upstream ISP's before it even reaches your web server - HTTP protocol handling is literally the last bastion of hope in a DDOS scenario.