Merion is my favorite course. It is the most beautiful course on wgt (well, after Pebble Beach) and forces you use good course management and hit a wide variety of shots to score well. Low scores are possible but a small mistake can put you in big trouble quickly. Some of the greens are infamous (Merion #5 is the standard for 'outrageous' greens) but they can be managed, mostly by staying below the hole.
I personally think that wgt did their best work in laying out this course. The yardage given is mostly accurate in terms of the distance resulting from a shot matching the reported distance to the hole. This course has trees, tough rough, brush, dirt, streams and significant elevation change. About the only element missing here is a lake.
If you can learn to appreciate the beauty and challenge of Merion, she will reward you with a rich golfing experience.