I've also heard the above theory from two different sources, rough running during and after take off. I figure when you hear it from several sources and now others here that perhaps it has traction, but investigstions will hopefully resolve these issues. Perhaps this played a part, but there could be another reason for the very slow forward speed. If the conditions down there were anything like northern Vic, then the wind was a howling southerly and very turbulent that day? Was it like that at YMMB? What's the glide speed of the RV?
The way the ATSB go, we may know in 4 years or so.