I agree that Inkscape is awesome, but the UI still could use some love in some places. What I am regularly missing, for example, is a widget that displays nested groups as intuitively as Adobe Illustrator does.

Inkscape gives you a possibility to search for elements with its XML-widget, but that one is really fiddly and doesn't support many really useful usecases (quickly toggling visibility, selecting multiple elements, regrouping by dragging elements out of a group...).