object inspectors

Originator: NO

Dockability is being worked on. As for "object inspector", please be more
specific. What exactly do you want to inspect that you cannot inspect with
the current set of dialogs?

Originator: YES

The settings for "Fill and Stroke" would also fit into the window "Object
Properties". I imagine that it is a matter of taste if a property list or
separate tab will be displayed.

The document metadata belongs also to the document properties.

I am missing the property display for group settings.

Originator: NO

Perhaps what you want is just XML editor (Ctrl+Shift+X) where everything
about an object is listed as XML attributes. I don't see a need for a
separate "inspector" for an application which is XML-based and provides
direct access to underlying XML.

Originator: YES

This XML view is not as convenient and user-friendly as the presentation
of property lists by other usual object inspectors.