I remember in New Vegas, just before the Second battle of Hoover Dam you start encountering elite soldiers from Legion and NCR, NCR has soldiers wearing stripped down power armor and Legion has some kind of elite legionaries, anyway i think it would have been cool if Bethesda included something similar in Skyrim, most soldiers in civil war wear really crappy armor, this is understandable, it's really expensive to armor an entire army with high end armors, but there could have been some soldiers during civil war plotline wearing better armor, as a sort of elite strike force, for Empire it could have been Ebony, it is known that the Empire keeps a stock of Ebony for just this purpose, Stormcloaks could have had salvaged Dwarven armor, they control some holds with Dwarven ruins in them so it is concievable they could have gotten there hands on a few suits of dwarven armor, of course since they are rebels they would not have acces to Ebony in any significant amounts so there elites would be inferior to Empire elites but Stormcloaks are inferior armor wise as it is, but a Stormcloak soldier clad in Dwarven stuff would still be superior to regular Imperial grunt, this seems lore friendly enough to me.