No Network shield just sits there. Only reacts to their black list. I think what I have read and misunderstood is that firewall has option of adding own domains, may be whole lists/hosts files. Don't know but would be cool. Pretty sure an Avast guy said url blocking was going to be moved to firewall though. Could be months ago and they changed policy at some point. Well it works but how big and updated black list is for free version is I don't know. There could be a difference. With security software that will typically be called "enhanced blocking of malware domains"
If you see comparison page free version does not protect against "high risk websites" or "Lets you safely browse suspicious websites or applications" that is url blocking they refer to so I don't know. Not many details about features.
5 is clearly better than 4 in most ways I can think of. More features too. How can he ruin that? I think 5 is just more of the same user friendly Avast marketing but with the difference that they now have better products to sell. Suites will always appeal to people and Sandbox is a very strong Pro feature. They are alone to have that for both 32 and 64bit? With all new shiny stuff they had no reason to cripple free version. Is still AV enough for most but own marketing like comparison page will of course be sure to make paid versions look better. They could not do that before because they had no products to "back it up"