A unique world type that has different rules. Here plots are not used, but rather, war plots. Everyone will have the same amount, perhaps there will be ways of earning some more through achievements on the war worlds, and these can only be used on war worlds. Here, monsters are more vicious, devious, and smell you from miles away. They are attracted to beacons and blood alike, and can damage and destroy the war beacons! Basically, think of it as a game of Tower Defense. With the unique environments in this game, I think this would add an exciting new type of gameplay, with unique structures you can only build on war type worlds, such as turrets to combat the hordes of monsters that would be drawn to your base. Once a war beacon is placed, a secret variable can trigger causing a countdown before a wave of monsters comes, and it only gets progressively more harder, wave after wave, until the beacon is destroyed. The incentive? Rewards that can be used in both war worlds and normal worlds, and better rewards will only spawn from certain mobs that will only spawn after certain waves have been survived. You could even implement group versions where people can combine their war plots and protect 1 singular beacon with harder/more spawning against them based on total warplots connected to each other.
I feel this should be added because the world seems a little too peaceful, even on the dangerous worlds things move at a certain pace that can get a little, sleepy. The best way I can describe the game right now is, “The Lazy River.” It’s a water ride where you’re just sitting in an innertube moving slowly down a stream with relaxing green scenery and some trees with shade. War worlds would provide building tension but would not be forced on players, so those that want a thrill can have it, but those that prefer relaxing can still have relaxing. Anything can be achieved with different worlds.