Next-Gen Firewalls...how are they different than Proxy or Parent Control?

I have been reading alot about these next-gen firewalls. Everytime I read this remarkably new idea I often think "sure its great, but how does it differ from what we already have?" Don't Proxy routers do the same thing in a sense? They redirect traffic to only go where you want it to go. A proxy can allow or not allow certain traffic to go through in and out.

Also I have a bigger stake to hammer into the ground: how does next-gen firewalls differ from parental control software? K9 Web security blocks certain websites from poping up according to catagory. You can also white list and black list types of traffic. So in other words just like a next-gen firewall you can disallow all traffic for lets say instant messaging in for example...same goes for K9 Web Security.

I fail to see any difference of all this other than the fact that a next-gen firewall works at the network level of computing, instead of the client level. Which all this is great, don't get me wrong....it is far better than just port blocking firewalls...but still how is this so revolutionary?

 I also like the idea that all these devices are put into one single device. I guess that is revolutionary. Kind of a swiss army knife of sorts for networking i guess.

I guess we can say that Blue Coat had it right from the start for "next-gen" with their ProxySG...