As you mention above, the prosecution were not required to pin the murder on an individual. This by nature should make the prosecutions task easier.
Their task didn't become easier in this trial, as they couldn't find sufficient incriminating flaws in the version of the accused.
Now, common sense tells us that since the best legal heads in the country of SA have spent countless months, weeks and hours on this case, and still could not provide enough weight of evidence to support their charge, only a few conclusions can be drawn :-
1. The prosecution team were not very good.
2. The judge was inexperienced and naive.
3. The prosecution overcharged their case.
4. The version of the accused could well be reasonably possibly true.
I struggle to believe that the prosecution team were not competent, and I know from Masipa's past that she is certainly not inexperienced or naive.
By international standards Masipa is quite inexperienced for a High Court Judge - let alone one handling a case of this complexity.
Indeed in NZ, it would be Nel & Roux who have the experience level to be appointed to the High Court bench.
She has only 7 years experience as an advocate. No decent experience as a prosecutor. Certainly never attained QC level.
In NZ she would not even be appointed to the District Court so soon.