It would make sense for the Empire to outfit their soldiers with clothes and armor suitable for the 'northern theatre of war', as the climate of Skyrim is very harsh compared to the temperate climate of Cyrodiil. Yet their soldiers wear skirts while marching across the tundra in snowstorms. There's been a few mods that have addressed this by adding pants to the Imperial armors, and by giving them a darker and more 'rugged' look, but they're all either disbanded, flawed, and/or incomplete.

In example, I think "http://skyrim.nexusmods.com/mods/7354/?" has a better look for Skyrim, but it's been abandoned, and the cape is part of the briastplate which makes it incompatible with both Winter Is Coming and Frostfall. The same seems to go for "http://skyrim.nexusmods.com/mods/16839/?", which looks even better as it's been darkened as well. Both "http://skyrim.nexusmods.com/mods/11272/?" and "http://skyrim.nexusmods.com/mods/41911/?" are great as well, but alas they don't add pants.

Perhaps there's someone here who's able and interested in making a consistent and compatible Imperial winter armor overhaul, in the spirit of the mods I've linked to? Ideally you might add pants to the Imperial armor types, give them a more rugged appearance, and ensure that they're compatible with Frostfall & Winter Is Coming. Hopefully at least one of the authors of the mods above would be willing to let you take over, as there's a quite a bit of great work in each of those.

Incidentally this reminded me of the TV-series 'Rome', where the Roman Consul Mark Antony (James Purefoy) wore a significantly darker, less ornamented fur plate armor while waging war in northern Gaul.

In any case, please consider this if you know your way around armors. Thanks.