Survival in the Medieval time would be a great idea I think.
Would love to see a version of this game but with Medieval type weapons, so its more of a cross between Minecraft (crafting) and Chivalry.
Instead of C4 for breaching walls, you could build wooden battering rams, steel tipped battering rams, Catapults, Siege towers and the list could go on.
Add different wall styles so you can make castle looking buildings.
Would increase crafting idea’s.
Not to mention hand to hand combat like Chivalry would rock.