Hi,
What would you say if new type of monsters were introducted – similar to Diablo’s boss+guards (boss with few random additional abilities, guards with 1) and packs of champions – rare monsters in groups of 4-5, each with random skills?
This would serve just as addition to the world. You wander and encounter group of mobs such as these. It’s very tough, reward is not exceptional. You may fight them for fun
Just an idea