If it is as simple as pilot error as everyone is convinced off, as the 1st AAIB report stated 'the aircraft appeared to be responding to the pilots control' then why have the CAA not lifted the blanket ban on Hunters flying.
I see no reason if this was the case that they could lift the no flying rule but keep the 'no aerobatics are to be performed and not exceeding xxx speed'. After all the Vulcan was only allowed to 'fly' but no aeros so same principles could be implemented. After all the Vulcan going down would probably do as much if not more damage than the Hunter.
The Gnats are able to fly again, after a sort period. Even the Red Arrows after their bad year with the loss of 2 pilots were not grounded for this length of time.
Think there is more information that the AAIB and the CAA have yet to release, after all they have only covered the basic facts of events on the day, airshow organisation, confirmation as to legality of the aircrafts permit in all their reports. No actual details as to the physical investigation of the aircraft itself has been provided as yet.