TCP/IP p2p coop would be nice with 2-4 people.
But it'd be some work still, would have to take into account how loot and such works. And more importantly how quests/progression works.
Only save the progression for the host? Or for joiners as well? What if a decision is made by the host that joiners didn't want? Killed of a character they wanted to live?
Would that transfer to their save too and so on.
Anyhoo, would still love the option of coop