I hope those things change and improve. It doesn't seem like they want to go the Firebug route with the CSS style inspector.
Granted, the most accurate way to present that override would be to display margin: 0 0 0 0, with only the first 0 struckthrough. But that deviates from the written code and becomes more difficult to track.
http://i.imgur.com/amWMy.png vs. http://i.imgur.com/ysH0a.png
(As an aside, note that FireBug doesn't know that the font color has been overridden by the font tag.)
I'm curious what changes specifically you would make to improve it?
This makes it very easy to scan because as a web developer, your brain is already trained to parse CSS syntax easily.
The controls in the webkit UI may seem richer, but they aren't actually as efficient as the simple code view that Firebug uses.