From someone who has used it, you are quite wrong.
1. Adding people to circles is manual, but the ui for it makes it quite easy.
2. A person can be added to more than 1 circle.
3. You are not limited to those 4 circles, they are just the defaults, you can add whatever circles you want.
4. When you post, you can assign it to be shared to whatever combination of groups/individual people/special categories that you want. However, the UI is simple and will remember your previous choices and default to your last one.
Honestly, without actually trying it, you shouldn't have made those claims.