The Paralympian was found guilty of culpable homicide last week after he shot dead girlfriend Reeva Steenkamp at his home on February 14 2013.
"I'm shocked," said Johannesburg-based criminal lawyer Martin Hood.
"I think she's going to get quite a lot of criticism from the judiciary and the legal system."
South African Attorney James Aveyard was also stunned at the judgement handed down in the North Gauteng High Court.
"The judgement itself took many attorneys by surprise as we were all expecting at the very least he would be found guilty of murder on the more serious dolus eventualis," he said.
Dolus eventualis murder, also known as common murder, means that the accused is considered responsible for the foreseeable consequences of their actions. In this case, that Pistorius should have realised somebody could die if shots were fired through his bathroom door.
"On the evaluation of the facts the very minimum you would expect would be for [Pistorius] to be convicted of was culpable homicide," Aveyard said.
"And I feel the state might want to have a look at grounds for an appeal on the interpretation of the law of murder eventualis."
Wits University criminal law professor James Grant also felt that the state would have grounds for an appeal on the verdict.
"The state is entitled to appeal only on questions of law and on sentencing and if my understanding is correct, this would appear to be a mistake of law that would entitle the state to appeal," Grant told Talk Radio 702.
With the court adjourned until October 13 to hear arguments in mitigation and aggravation of sentence, Aveyard is confident the judge will be persuaded to impose "a fairly strong sentence".
"I'm quite confident the state will be in a position to persuade the judge to give a fairly strong sentence," he said.
"Realistically though, I don't see him getting a maximum sentence of 15 years, there are too many mitigating factors."
Pistorius' full jail term will be decided by Judge Masipa after she has heard arguments in mitigation and aggravation of sentencing with culpable homicide - where it is deemed that the defendant was negligent but had no intention to kill.
The judge extended Pistorius' bail and adjourned court proceedings to October 13 when arguments in mitigation and aggravation of sentencing will be heard.
Pistorius was charged with the "wilful and intentional murder" of Ms Steenkamp. The 27-year-old had denied the charge as he claimed that he mistook her for an intruder after hearing a noise in the bathroom of his home.