I recently started playing again and I downloaded the King of Riverhelm mod, I think it would be pretty cool if you could send out a squad of soldiers lead by one of your companions to complete quests, maybe they could return in a few days with the item they were sent to find, with a chance to fail based on certain parameters. Furthermore it would be cool to be able to occupy each of the holds, attack their towns and install a Jarl loyal to you, then see your own soldiers patrolling the towns and surrounding wilderness. Maybe at a certain point there could be a massive Thalmor/Imperial invasion or Stormcloak uprising(with hundreds and hundreds of npcs) trying to take back the province.