Bugthesda is a terrible developer using a terrible engine.
I feel like people who ask this question believe co op is a magical spell one just casts on a game.For one, would you enjoy playing co op and getting disconnected evey half hour due to freezes? That's just one simple reason.But hey, I understand the want for co op. Just, think about it for a few minutes and you'll realize it's just not feasible.BTW No one is stopping you from creating a DnD campaign based on Skyrim. Sounds kind of fun IMO.
You are not allowed to request a sticky.