[joe_the_user]

"This game takes like 8-12 hours"

I found the best Diplomacy framework is a hard 15 minutes/turn limit. After 15 minutes, your moves are down on paper or they don't happen. This yields a 4-5 hour game.

By "best", I mean, "it's fun, it's intense and it's done". I see a lot of variations being described along with notes they became intolerably intense for people.

Which is to say, this isn't a framework that needs help to be made more engaging. Keeping the excess-engagement genie sometimes in the bottle is more the challenge here.