The article is largely talking about the federal penalties for going to trial, where you have to be 80% sure you will win before it makes sense to reject a plea bargain and go to trial.
Um, NO.
He may be guilty as sin, but the government has to prove it's case. If it doesn't prove the case, he walks irrespective of whether he is a bad man because sometimes he ISN'T a bad man.
Your anecdote seems to confirm this.
For the second court instances, which handles appeals from the lower court or serious cases (potentially leading to 6 years or more imprisonment, which in Norway pretty much limits it to murder, serious drug related offences, rape or other serious sexual offences or particularly serious robbery cases), there is a jury and a panel of three professional judges. The jury is selected from the same pool as the lower instance, but generally the selection takes into account experience, so that it generally consists of people with experience as lay judges from the lower court instances.
Which means you'll usually face a jury where the members have previously participated in deliberations with a legally trained professional judge.
If the professional judges do not agree with the finding of the jury, they can set it aside if unanimous (in the case where the jury votes to acquit) or with two votes in the case where the jury votes guilty (and the professional judges wants to set the guilty verdict aside).
If the judgement is set aside, something which is very rare and usually happens only if the jury made obvious substantial errors, the case is retried with three professional judges and four lay judges.
It has warts, but the system with lay judges means that you don't face a group of people who don't understand the system with no corrective input, yet at the same time it still quite frequently happens that the lay judges overrule the professional judges (and the judgement is only rarely overruled), or that the panel is split with a mix of lay judges on professional judges in the majority.
The jury system is related to the original democratic ideals: educated, responsible citizens which can be trusted (in aggregate) to take good decisions.
What you want is a society where you have more jury like systems, which would encourage the education of the people and especially educating their critical sense.
You also want low enough penalties so that jury mistakes are not too dangerous.