I have the Theta SK's.
The cut is slim, but works for me. I also prefer less bulk, and the cut lends itself to more than just skiing, but winter snowshoeing, etc.
The bib part doesn't come up too high, and the back brace area is made of a light stretchy nylon.
It gives just a little bit of warmth, so with a lighter top, it helps out a lot.
With a shorter cut jacket, it cuts the wind/snow coming up and helps you to stay warm in colder conditions (trapping more heat, less cold at the low back).
The above design cues is why I got them.
But yeah, mine are cut slim.
IF you can't find `em on sale yet, wait a bit for the new "pro" gore-tex gear to be fully released, and retailers will try to sell off the "old" stuff.
Check the arc'teryx site, it's updated