Three thoughts that it sparked: first, a frustrating omission is that Crawford doesn't explain the overall structure of the judicial system in Ireland, or how it compared to the English model that it was to an extent copying. This leaves the lay reader a little at sea - it's obvious enough that the Court of Castle Chamber was the most important piece of the legal jigsaw puzzle, but one gets very little sense of the number and size of the other pieces.
Second, I deal with countries today which struggle with the rule of law, where courts have basically always been an extension of the executive branch of government, and the notion that judges might make important rulings that are based on legal principle rather than what the Prime Minister wants is naive at best. But it's actually really important that courts should be independent and work on clear legal principles, and that they should occasionally come to decisions that are inconvenient for the government of the day (the Irish Court of Castle Chamber is not a good example here). For citizens inside the country, the legal system is ideally a protection against government rather than another manifestation of state power. For external investors, it's more straightforward to pay lawyers to get as good a result as possible within the rules than to bribe officials until you get the right outcome. Those of us who live in countries where the rule of law actually does apply sometimes don't appreciate its importance.
Third, one particular incident from early in the Court's existence struck me as particularly important. In 1582, the Chief Justice, Nicholas Nugent, was suspended from office and then tried for treason, on the grounds that he had supported two of his nephews involved in the 1580 Baltinglass rebellion. Treason trials required two witnesses for the prosecution; in this case there was only one. Nugent's nephews were safely in prison and were not executed (one died in prison years later, the other was pardoned). The Court of Castle Chamber got deeply entwined in the conduct of the jury trial to ensure the right outcome, which was that Nugent was swiftly found guilty and executed. It was a display of lethal executive power against a leading member of the judiciary, and it worked; and in restrospect it was a precursor to the use of the Court as an instrument of oppression in the following century.