Pretty familiar with this topic, as Sugarloaf is home to us. My wife's a life long skier, and a good one, and she does not like being cold. At this point, will not ski if she's cold. I have a few ideas, most of which you're probably well aware of. Head, hands and feet all need to be warm, or the core will chill. I find that a lot of people are a full layer "short" in terms of what they wear on the top when they first ski at Sugarloaf. My 25 year old niece is a great skier, former racer, etc. and a year ago her first comment was "damn, I love this place but I always forget that extra layer the first morning."
I have a couple of Cloudveil shells that I really like, and they'll last me a lifetime as they don't get much mid winter wear at home. Spring stuff. On the average winter day at Sugarloaf, my wife wears a mid weight Patagonia base layer, a light fleece T-neck, and a heavier fleece pullover. On top of that it's a very well insulated coat. On the colder days, the fleece pullover might be replaced by a Patagonia puffy pullover, or a Patagonia puffy vest might go over the fleece{or both!}. Has a few jacket options. The warmest is a down jacket, a bit on the long side, that has a down insulated hood big enough to cover her helmet on the chair rides up. I might consider a good vest as an extra layer, or re-thinking the shell as outerwear. Even the best shell for some folks requires a lot of layering on a cold day up there. My advice on the outer jacket is always buy up in size, so that you can layer a lot. As you well know, it can be cold, damp and windy....all at once. Maybe she needs the "average cold" jacket and the "really cold" one?
Three other constants for us. We normally change our socks midday, and may use a bit of baby powder. My wife always wears a neck-up pulled up high, and that often gets changed midday. She also wears a synthetic glove liner....inside a Reusch mitten, which already comes with an internal glove. And, we will often duck into a lift shack, or the patrol hut at the top of spillway to warm up for a few minutes. Always seems to mean something to my wife when I suggest it! After 30+ years of skiing together, I'm better at it.