For using GxInspect without GExperts: somebody inspecting their own Delphi application would rather click through a form tree, see properties in a grid and a screenshot beside them than type CONTROLS and read text.
The protocol needs nothing new for it: FORMS, CONTROLS, GETPROP, EVENTS and SCREENSHOT are the whole data model such a window would show.
It is a VCL application in its own right, not an afternoon's work, and nothing depends on it: the console client covers every use there has been so far, and -f, --stdin and -i cover scripting.