Actually, it indicates a problem. I was also not aware of the geometric spiral option until peter pointed it out to me :) To me it suggests that this functionality needs to be made more visible.
It will be made more visible when I (or anyone else, volunteers welcome!) have time to move the contents of the Tool Options dialog to the secondary toolbar at the top of the window.
As for using node editor for tweaking shapes, now it's hinted by the default statusbar messages which say "... Use node editor to {round corners|make an arc or segment|edit the star shape|edit the spiral}" for the four shape tools.
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