I am not a Dev, so I do not have details as to why the patch would not be rolled back. I would suspect as Reebont mentioned, it could also take a significant amount of time and is not as quick a fix as it may seem.
With regards to the timeline, as I have mentioned in other posts, it is very difficult to estimate the timeline for the release. As Sam highlighted in his post on the patching and submission process ([PS4/XB1] Dev Update on Interaction Bug) there are a number of factors that can eat up time. If that changes and an estimate becomes available as things progress, then the community will be updated.