Hunter provides some very steep terrain for the Catskills. Lower K27 is one of the steepest runs I've seen in the East, although very short, and the entire West Face is some of the best bumps in the East with continuous bumps all the way down.
Gore's top area provides some good steeps. The Rumor and The Lies are very steep, the Rumor being a longer version of Lower K27 @ Hunter and the Lies being a longer version of Ripcord @ Mount Snow.
Whiteface provides some of the best sustained steeps in the East. Although lacking bumps, the Olympic trails drop 1500 or so vertical down to the midway (still another 1500 vertical to go to the base) of continous groomed steeps, the steepest and longest groomers I've seen in the East. The Slides, if your lucky and their open, are by and far the hardest marked "runs" in the East.
Jay Peak has some steep stuff spread throughout the mountain in its plentiful glades. The Ridge area has the steepest pitches I've seen in the East, although off the map. The Face Chutes and Tuckerman's drop from the summit and both have some of the most technical sections I've seen on marked trails in the East with some real no fall zones. For example, the Face Chutes requires the navigating of some 20+ foot cliffs on 35 degree and narrow pitches. Everglades and Staircase are long glades with steep top parts, and Deliverance is probably the hardest glade on the mountain, starting off with a long and steep 8-10 feet wide chute into a bunch of trees.