Many of the high-end Irish courses had sites that could be considered excellent on one hand (large country estates with grand houses, natural water courses and mature, specimen trees) and very average on the other (relatively little land movement on heavy, clay soil).
But there’s no doubt that they followed a design philosophy that is out of style (e.g. containment mounding, excessive earth movement relative to the site, long curves in the shaping, lack of undulation in the fairways and greens).
If a modern day crew-du-jour got their hands on those sites, they would look very different. TD / Renaissance would perhaps have created a look similar to St Emilion… others might have stuck to the frilly edged style…. Who knows… All I know is that a few of them could have been better than they are.