I have skied all the eastern trails mentioned at one time or another, Magic lift lines, Goat (Starr scared me more than Goat but probably because of that entrance), Castlerock, Paradise, White Nitro, the t--bar line at Pico, Lifline and others at Smuggs, Face Chutes, etc. at Jay Peak, with the exception of Tramline and Kinsman's glades at Cannon. Not sure if it was mentioned but Tramline looks sporty and was not open for skiing back when I used to sometimes ski Cannon. Never been to Whiteface when the Slides were open but, while steep, I don't think they are THAT steep; I read 35 degrees somewhere. None of the above runs I have skied would I consider as one of the most intense runs in the US. For me intense has to have some consequences. Scariest thing I have skied in the east was Tuckerman Ravine but that is not a ski area run.
The most intense run for me was the second time I skied Tower 3 Chute at Jackson Hole. The second time because the first time I was a young 33 and it was snowing like crazy with a couple of feet already underfoot. I couldn't see what I was getting into and just enjoyed the heck out of it. The second time I skied Tower 3 I was 59 ( yeah I didn't go to Jackson for a few decades - my bad.) the snow was a little sketchy and I could see that if I fell before I got around that first corner I was gonna slide really fast into a bunch of rocks. I skied it slowly, cautiously and in control.
I am not a super skier but I am good with tactics and I don't panic - that never helps in any situation anywhere.
There are a lot of lines at Snowbird and Alta and Big Sky that I will never ski and I am sure the same holds true for Whistler/Blackomb and plenty of other mountains. I mostly avoid the really intense slopes these days. At 63 I still ski at a fairly high level but shit just looks steeper and scarier to me. I always relate this story about skiing with my son at Jay Peak maybe 5 years ago. We were stopped on a slope and I said to him, "This is really steep!" He just looked at me like I had 2 heads and pointed 'em straight down. Freaking kids.