Let's assume what suggest is correct.... "Will a judge (having primarily been trained as a lawyer) going to properly understand every bit of expert evidence presented to him or her?"
If the judge was a lawyer specialising in Family Law they would have decades of experience not only in the law but in reading and analysing expert reports every day/week/month/year before they become a judge and then it would depend on the judge as to how many years/decades of experience they have in determining cases that have those reports.  To assume the judges and lawyers do not understand what is contained in those reports is really a stretch and to assume the reports need to be dumbed down is an outright insult.   
As for the other assertions, perhaps to some degree they have some relevance, but as a whole, looking at the judgements that come out of the Courts in recent years how many could you read and say the Court got it wrong?  From those you believe the Court got wrong, how many of them could have been argued/presented better to get a different or more just outcome? 
There would be very few cases that would fit the criteria you portray where the Court itself is simply in error.  
May we suggest if you believe there are such cases that exist, let's put up a discussion, reviewing the case(s) and seeing if they could have been argued better or whether the Court itself is to blame for an unjust outcome?