To extend what Nitro said: wonder why you actualy like dungeon keeper. Ask yourself if it would perhaps be way cooler to design a dungeon in a mountain, or underground while you start at the surface. Instead of being evil, you play the good and should defend yourself against evil forces. You can still use every aspect of dungeon keeper (e.g. build a lair, a training room, a chicken room) but put it in a totally different context. Extra additions may be the capturing and training of wild animals and use them in wars. Train wild elephants to war elephants, tame dragons, breed hordes of hunting dogs... Just an idea .

Perhaps you might find it worth to take a look to dwarf fortress and settlers instead of just dungeon keeper 1. Dwarf fortress is a very difficult game to learn playing, but it is very very extensive in what you can do and build. And Settlers is graphically beautiful to look at, and might give you different ideas.