i actually think a lack of z-level and more interpersonal relationships (relative to Dwarf Fortress, where you have interpersonal relationships but hugely you're focused on hundreds of dwarves at maximum) is both what makes rimworld different, and what can make it weaker.

as far as colony management games go (that might not even be the right genre for these games), rimworld lets you tell stories between people by its nature, whereas dwarf fortress lets you tell stories of a fortress.

however, dwarf fortress doesn't have steam workshop mods that let you have milkable catgirl maids, so, you know.