Benedict saying he wasn’t sure how Mofftiss would be able to pull off s4, but then getting on board after hearing a more detailed pitch, makes no sense if the season were meant to be taken at face value. At face value, the season is: Mary’s past catches up with her and she redeems herself by taking a bullet for Sherlock, John grows angry with Sherlock for not protecting Mary, Sherlock puts himself in danger in order to snap John out of his depression and make them friends again, we find out Sherlock had a secret sister the whole time who killed his dog, which was actually Sherlock’s childhood best friend (and the sister reveal couldn’t have been a shock to Ben because it was in the version of the script for HLV sent to the Emmys).
Nothing about that makes you think, “Gee, how will they do that?!”
Unless the audience had wool pulled over their eyes in a major way somehow.