I know so far that we've only had two bosses who are really not too hard, but we might as well make the best of it.
So I suggest that the amount of time it takes to kill the bosses should be timed and we can see a high score list somewhere in town.
The timer starts when the party steps on the party button and ends when the boss dies.
The high scores will be separated into categories by the number of players present during the boss fight to make the scaling of boss HP constant for all categories.
I would suggest it for other maps too, but they're always changing so it would be unfair in many cases.