I'm going to spitball some dungeon ideas.

> You're chased by a demonwall or some kind of boss the entire run. Various adds along the way. Doesn't have 3 boss structure.

> Vehicle sections in a dungeon like the magitek armor in praetorium. Could involve flight or underwater travel, such as mounting a submersible and firing torpedoes at obstacles.

> Dungeon where the floor collapses and you dodge things during the fall, like the byakko skydive fight.

> You set minimum item level, the tome and gil reward is increased. Gives a reason to do harder instead of faster.

Btw the Expert roulette could be reserved for dungeons that are actually harder than normal difficulty. For dungeons that are just new, they could go straight into a lv80 roulette. Make expert mean expert.