Why not use a new unifed configuration manager like the other interfaces (Kde, Gnome, Xfce, Lxqt, etc) ?
It is better to have just one and it is easier to mantain and use,for example you can take one of the first version of gnome settings and fork it.
No, because you have lot of apps in the start menu (sound, mouse, displays) instead of just have one configuration app like other interfaces
mate-control-center it’s like a shorcut to open all the configuration apps individually but isn’t a unifed interface with all the configurations inside
Unified window would be only useful for upstream MATE config apps. We can’t embed 3rd party apps into it…
That doesn’t look like a MATE app 
What about 3rd party apps? I see Ubuntu One, additional drivers installer and backup tool there. I don’t think they’d be launched re-using the same window.
Honestly, it just need updated really badly, as well as the default icon theme. It looks horrible. When we look at other desktops/desktop environments, and we see the way that some of theirs is set up, we should be taking notes, trying to help developers, and or other communities to come up with some new/fresh/creative ideas. Lets use Deepin or Ubuntu Kylin Ukui desktop environment. Very pleasing to the eye. That’s the way its supposed to be. Anyways, that’s just my personal opinion.
Many people like the modular nature of MATE Control Center and i believe it should stay on that way.
I agree on mate-icon-theme being ugly (because gnome-icon-theme has always been fugly), i always liked the Mist icons more.
