I have hesitated to comment so far on the verdict. However from the wikipedia article on the trial, I read:
The defence of Pistorius was that, in shooting at what he believed to be an intruder, he mistakenly believed he was acting in self-defence, and as self-defence excludes the unlawfulness requirement of criminal liability, an act in valid self-defence is lawful. Technically his defence amounted to a claim that he did not intend to act unlawfully. If he could raise a reasonable doubt in his favour that he was mistaken, as he claimed, he is entitled, under South African law, to an acquittal on the charge of murder. The court then considered whether this mistake was reasonable – one that a reasonable person, in his circumstances, may have made.
If this is correct, the test is NOT whether Oscar could have acted differently, but whether a reasonable person, in his circumstances, may have made the same mistake.
I fail to see how this possibility can be excluded. People make mistakes all the time. Unless there was Malice in the mistake Oscar made, I do not believe he should be held to have committed a criminal act. And I see no evidence of Malice, or any intent to act for his own gain, other than to defend himself and Reeva.
To me, the judge seemed mostly concerned with explaining how Oscar was not guilty of murder, and failed to explain adequately her reasoning on the proof beyond a reasonable doubt that he was guilty of manslaughter.
Just my lay opinion. I could be wrong.