So I predict the Holds (which will be at war with each other) are joinable factions for which we can do quests, rise through the ranks, and ultimately unite to face to threat of the Dragons. Along the way there will be some choices to be made (do I serve the old-school axe-weilding Nord tribe, or ally myself with a mage-centric clan?) Joining one faction may flag you as an enemy of other factions. If you see a party of soldiers travelling the highway, check their insignia before revealing yourself! Full scale battles could also be possible...
A unified Fighter's/Mages Guild wouldn't work in a country torn apart by civil war, and choosing between political rivals sounds much more interesting.
If this turns out to be correct someone owes me a fishy stick.