People consider extremes higher than midcore?!

In 9+ years of playing I've only been to DF extremes where the party failed to clear 5 or so times. Extremes are midcore content. It's challenging, but doesn't take a long time to practice. It's perfectly doable with randoms on the spot, but it's not guaranteed you will clear while they're the highest extreme.

The midcore content in this game:
Extreme trials
Unreal (ruined by the arbitrary way they replace fights)
Delubrum Reginae (ruined by being a large scale instance, which enables a lot of dead weight who intentionally don't contribute much if at all)
Deep Dungeon (if going past the minimum floors)