GENUS IDEA! We have different enemy for different MAPS! A Pre-historic themed map like the one we play on now, for dinosaurs and mystical creatures, A Pre-Apocalyptic world where everything is overturned by ravaging bandits and marauding foes, making survival the real enemy (Zombies would just be available in special areas, like Fallout). Or an unknown world set in the near distant future which sets the player in a warzone, to make it a DayZ clone or a CoD players dream, <[It'd attract more gamers too] Personally, im for dinosaurs, but because dinosaurs aren't for everyone, the world can evolve, the more minerals you mine, the more adapted the world will get, the more dinosaurs you don't kill, the more rock hitting the game would get, make it more evolving, the decision you make affect the game you play, Make the game interesting and enjoying, make it to your own imagination. Ive spent alot of time on this paragraph so.. Make your mind up.
Fan modded servers is what u talking about.