Points to consider for cold weather pants:
1. Pants should be loose so's you can wear insulation (poly fleece) under them without binding. Polyester fleece is 2x the insulation when damp as wool, much more abrasion resistant, and machine washable. (And, silly me, I still like my German and Swede wools.)
2. Pants should be wind resistant. (The "boiled wool" of the German pants do this too. But why are they on the surplus market? Nylon and polyester.)
3. I like belt loops, not silly elastic, so you can keep them up. (Or you can use suspenders.)
4. I like exterior pockets. (Can you believe pants without pockets. Please!)
5. Zippers calf to ankle are nice to allow pulling over boots if absolutely required.
6. Gore-Tex (and the like): The theory vs. reality. They don't breath with a film of water on them (Vapor pressure can't overcome film strength. That's why they put water repellant on the outside.)-- not an issue in really cold weather (below 25 f). They don't breath enough if you're active -- an issue whenever you're active. Wet is wet, whether from outside or inside. Plain old nylon works better unless keeping rain out is an issue; that Gore-tex does pretty well. [Side note --> Gore-tex chaps. If the parka goes down far enough so there's no gap, the chaps keep out cold rain and allow ventilation of critical areas.]