A little late to this thread which is very long. But I read through every post and the entire accident report. This sort of accident happens every once in a while. As the report mentioned, there was King Air in California that crashed with the trims(including a lot of rudder trim improperly set), and another accident in Tennessee due to the rudder trim. I also remember a 737 crash in New York for the same reason.
The reality is that this will continue to happen, however, there is a way to prevent it. Check what I call your killer items just before takeoff after having finished finished the Before Takeoff Checklist. It has been a very long time since I flew a King Air but off the top of my head, I would suggest taking 10 seconds prior to entering the runway to check the flap position indicator, elevator and rudder position indicators, autofeather armed(if installed), position of fuel selectors/pumps and pitot heat. Perhaps there is more of less that can be checked and it can vary from aircraft to aircraft, but all of the accidents I just mentioned would not have happened if this had been done. And while some would say the same thing about if only the checklist had been done properly, the report gives us the reality of how the checklist is frequently not done properly for a variety of reasons. And that will continue to happen no matter how emphatic some are about doing the checklist properly.