I've been having fun doing the platform jumping at certain islands like the Shores of Gold and that arena rock in the center map of adventure mode; and also jumping around the ships in the Legends Hideout. I started to think a fun addition for Legend's content would be dungeons or basically an obstacle course for us to "speed run" through, and have timed leader boards refreshed with a new course every so often. The obstacle coarse would be accessed from a portal in the Hideout and work like running through the Sailors Bounty TT or the Belly of Shores of Gold.
I'm not really thinking of this for rewards other than the bragging rights for topping that leader board. Weather or not it's implemented for legends or leader boards; I just wanted to say the few obstacle courses added have been a fun experience for me.