Surely the AAIB reports do lay blame where that is appropriate?
So for example they may say that the crew failed to do this, monitor that or whatever so the a/c approached at the wrong speed yada yada and crashed short. etc
Of course at this point everyone will duck and weave and seek to lay off blame elsewhere. The training was inadequate, ATC was confusing, the weather was sh*t, SOP prevented us: and off we go.....
How about the argument from the other side that if the AAIB report looked like putting the blame on the pilot, then rather than the CPS seeking to stop publication it is the pilot's legal team might be seeking an injunction to stop full public publication of the AAIB report so as to not prejudge the outcome of any future legal actions.