I feel like some of the taverns, and more specifically the Inns in Skyrim are pretty barren when it comes to people.
Even the Bannered Mare in Whiterun only has maybe four or five people in it, I'd like to see at least ten.
Such Inns like the one in Riverwood, Falkreath, and Winterhold are enormous buildings! I speak of the ones with the fire pit running up the middle, rooms branching off. There are seldom more than five NPCs in these buildings.
It would be nice if a mod could be made to make the Taverns/Inns feel more crowded and bustling at night.
I've noticed that there seems to be a decrease in the reliance of NPCs on the "schedule" system that was present in Oblivion. Very few NPC's make trips to other cities, visit bars/taverns, or even seem to venture out of their own houses with any semblance of regularity. Perhaps more frequent visits to the local pub could aid with immersion.