Would love a redesign of the system.

Something like a treasure cruise style content that draws from the treasure dungeons.

Start out by building the airship or submarine. Then you gather a party, plan a course and set out.
Then you're placed on a big map with the airship/sub taking you to the first location.
During the travel on airship you can get attacked by monsters and you need to defend the airship, if it gets too damaged you'll return to base. Not sure how to do this with subs.
When you reach a location the objective will be random (multiple monsters, boss monster, puzzle, etc).
Each location you clear will reward a treasure chest.
When you return to base the airship/sub will refuel(cooldown timer)