IMHO the only reason they would have for unsealing these documents at this time is if they are aware that the documents have already been accessed in their entirety and will soon be made available by a third party. Furthermore they must know that the intelligence contained in the documents must be damming enough to cause a shift back to the right on the political scene. Obama can take the hit for keeping the documents sealed this late into his presidency but it would be hard for them to assert that Hillary actually won the election if even democrats find the contents odious. If the contents were not already available to a third party they would be able to alter the contents to whatever they wanted and no one would be the wiser.