I sincerely doubt Nords will be able to be mages.
Nords, Redguards and Orcs I see as fighters, while Bretons, Dunmer and Altmer will be mages, and Bosmer, Khajiit and Argonians will be the rogues. Just a hunch I've got... there might be variations within those archetypes (Bosmer = rangers, while Khajiit = thieves and Orcs = beserkers and Redguards = paladins, for example), but I guarantee that specific races will be locked into specific classes.
Nords had a proud history of magic (College of Winterhold, Shalidor, the Thu'um) up until the Oblivion Crisis, the Great Collapse and the Great War.
Spoiler
As, Tsun says in Sovngarde:
"Well met, mage of Skyrim. The Nords may have forgotten their forefathers' respect for the Clever Craft, but your comrades throng this hall. Here in Shor's house we honor it still."