Certainly the worst part of the report was in the many parts that he is now retracting, that the IDF purposefully targeted civilians. He now says that the "fact-finding mission had no evidence on which to draw any other reasonable conclusion" when the report was written. But in reality, if he had looked at both the history of how the IDF acts in war in general, the specifics that were known about how the IDF acted in Gaza, and how wars in urban combat zones are generally waged (i.e., in Iraq), of he was fair he would have easily concluded that the IDF was not purposefully targeting civilians and that they went out of their way, indeed even above and beyond, to avoid targeting real civilians (while Hamas was dressing up its fighters in civilian clothing.)
It appears that now, two years later, he is impressed that Israel is conducting investigations into acts of individual soldiers. Yet this is how the IDF always acted.
His belated retraction also doesn't note that much of what his report said was known to be false at the time the Goldstone Report was released, as I and others have documented quite exhaustively. His report had a clear and consistent bias where Israeli claims were treated skeptically but Hamas claims were believed without reservation. To come back 18 months later and lamely admit that Israeli claims were indeed found to be accurate just shows how biased he was in accepting problematic testimony then.