Right. How could he plead not guilty if intentional murder is that clear cut, black and white, open and shut? The state is charging him with intentional murder and now they have to prove it. If it's murder regardless, since we know OP is the one who shot Reeva there'd be nothing for the state to prove and nothing for oscar to plead not guilty to.
Surely that is a question for OP and his team.
Many people have pleaded not guilty when the case against them has seemed obvious. That is their right. If they then get found guilty, any mitigation which they might have earned by a guilty plea goes down the pan.
My understanding is that his defence team will try to to show that his statement in which he did not realise Reeva was in the toilet and in which he was in genuine fear of his life (and therefore justified in firing the gun four times) was a believable version of what happened.
If believed, then the judge may find him guilty of culpable homicide and use his fear as a mitigating circumstance thus reducing the length of his sentence. I am not entirely sure how much mitigation is allowed, but have a feeling it can result in something as 'lenient' as a suspended sentence in exceptional cases. So, there is still everything to play for from his point of view and that is why there is a trial.
I am amazed that some (possibly not on this board) are suggesting that if his team can show he did not think it was Reeva he was shooting, then he should walk free.
Regardless of who was behind that door, he went to fetch his gun and then shot to kill - and succeeded. So even going by his own version of events, i believe he acted recklessly enough to warrant a significant custodial sentence.
Given the deeply suspect and bizarre affidavit and the testimony of several witnesses, i lean towards the blazing argument, complete loss of control and deliberate shooting explanation.
It will be very interesting to see how the cross examination of OP goes.