Honestly, I think the game would be improved by the addition of a thousand or so 'static' npcs that simply wander around and do things. Having in-depth characters that you can interact deeply with is great and all, but when you have as few npcs as Skyrim does because of this, then the game feels empty. Yeah, it's Skyrim, a harsh land sparsely populated by hardy Nords. That said, major towns such as Whiterun (heart of the region and trade capital), Solitude (capitol of Skyrim and regional Imperial headquarters), and Windhelm (ancient, large city, nexus of the Stormcloak Rebellion) should all be choked with npcs, even if the rest of the land is as barren as it is now.

wouldnt even need that many. the TIE mod for oblivion added around 500 to 600 npcs and it was just about perfect. most cities actually felt alive but not overly jumbled. the fort attack missions for the civil war quests are embarrassingly small. granted im used to playing with 250 characters on screen in mount and blade but seriously you only get like 16 or so in the fort battles at one time. the worst part is that you see soldiers just magically appear right in front of you with no rhyme or reason.