My sense is the original Goldstone report was near the border of veracity at the time, just barely confident given what was known at the time. Now, it is only slightly less confident, but on the other side of the doubt divide. Now, it is doubted. Specifically, what is doubted is what can be considered an admissable scale of military action. Sets of individual actions that would be inadmissable themselves if the scale of the whole operation were now regarded as legally admissable, would then become legally admissable as individual actions. They would change color from red to yellow, or yellow to blue. The contributing concerns that I have about it, are that by my read, Hamas insisted that Israel undertake some military action, that Israel was responsible to (more than a "right" to). And, that statements made after the ceasefire by Hamas ("we are thoroughly prepared for an Israeli ground invasion" and "we will wipe the Gazan streets with Israeli blood", made by leaders of the Al Qassam Brigades) compelled the IDF to pursue a militarily "careful" approach. The Israeli electorate demanded it, in demanding that they undertake a strategy of minimum risk to soldiers. There were likely other long-term strategic options than to get to that choice between bad options, but once there, it was plausibly not an illegal scale of operation. I think Goldstone accurately conveyed that slight shift, from "war crimes" to "war".
from the article: What exactly did Goldstone 'retract' from his report on Gaza?