The treeview with the devices does not stand out much, it could use a slightly different background color, for instance the light gray used for the "content-view" css class in adwaita. The +, -, and gears buttons under the list should be a "secondary" toolbar attached to the treeview, following a pattern used in many other placed in gnome. The gear button does not do anything here most of the times... I have no idea if that's a bug in itself, but when it does not do anything it should at least be insensitive.
the correct css style to use for the toolbar is "inline-toolbar". You can see an example here http://git.gnome.org/browse/gnome-control-center/tree/panels/bluetooth/bluetooth.ui#n67
These should all be fixed in the latest build of anaconda. Thanks for the info.