But if you know your way around, there are few tools that can be used to change a lot of Gnome related functions nonetheless. Anyway, although this app won't be shipped as a default app with the Gnome3, still if you want to change somewhat reasonable amount of settings in Gnome shell then you may want to consider using GnomeTweakTool when they release it officially.
Here are the main features...
*. Change Gnome shell themes (not only the applications based themes, but with this option, you can easily change the way Gnome shell - dock, panel, etc looks like).
*. Changing GTK themes and icon themes (only applies to applications).
*. Fonts and title bar customizations.
*. Various Nautilus based optimizations.
*. Disable/enable icons in menus.
*. Desktop icon customizations.
*. Title-bar click action change.
*. Various font related optimizations (hinting and anti-aliasing)..., etc.
This is not yet officially released, but it already looks really promising... ain't it? :).