Amaral led the investigation, he was party to everything which occurred, as PJ Coordinator he liaised with the British police and the Forensic Science Service, he saw the reports which came in following the disappearance, the dog inspections, he oversaw the witnesses and arguidos being questioned, he saw their reactions and you in your wisdom think him poorly informed. 
I would say he is probably the most informed person in the entire investigation.
I have to disagree with that Angelo. As he never met, spoke to, or interviewed the McCanns himself - then imo he certainly was
not ''party to everything which occurred'' - and as interviews were not recorded - then all the information he received came to him second hand - and also 'opinions' of the McCanns could only always be other people's opinions - not his own.
Never having made personal contact with them meant he could not make his own assessments of them - both as genuinely distraught parents or as credible witnesses. That put him at a disadvantage IMO.
Why he chose
not to make his own assessments of them is a mystery to me.
AIMHO