Bartlebad

This is the exact same thing they've done for the past couple editions, so Legends as a thing isn't new. I see this more as, hey, these models are old as hell, aren't made anymore and we don't want to spend time making sure they're balanced for tournament play, so here's rules for you to play them in casual/Crusade games, have fun.

If you're looking for something in the same vein as Dwarf Fortress, there's Rimworld. It's the game I hit 1000 hrs played the fastest, thanks to the ridiculous amount of mods available on the workshop.