Personally knowing the pilot very well I would add my personal opinion that planning was not an issue in this tragic event. Andy plans and executes everything he does with the same high level of precision and professionalism that he displays when flying.
I will not comment further on the accident, that is for the AAIB to do.
As far as limiting airspace to that directly over airfields or stopping the overflight of roads you may as well ban flying. A 10 second pause in a routine whilst figuring out a master caution light in a jet doing 420kts will put you over a mile from where you started. These are the velocities and energy we are dealing with. A rolling turn back, or half a Cuban 8, is a standard manoeuvre to put you back on the display line. Trying to plan any display that doesn't overfly a road in the UK is, in my opinion, impossible. The display line for Farnborough crosses a housing estate and a bypass at its eastern end. Do we ban that? I would humbly suggest that performing high energy turns whilst trying to stay withing a tightly constricted display space might be more dangerous than what we have now. It is not easy to get a display clearance, the safety criteria to be adhered to are rightly stringent. Lets not add unnecessarily to that burden.
It was a terrible accident and I await the AAIB report as much as anyone.
My thoughts and wishes go out to all those involved.