If my theory above is correct about how Xbox One games apply patches, that means patches are able to fix the game to a much larger degree than last gen. On 360 for example, if there was a game file that needed replacing, all they could do was write some code in the patch which aided in fixing the issue; whereas now they can actually replace that file with a new version...... In the end it means great things for fixing games, but bad for us because patches are large.
I of course could be wrong about all this patch stuff, but it does explain the large sizes if correct.