In FFXIV 1.0, Toto-Rak had 3 different end bosses you could fight: Easy, Medium, and Hard. The path to get to each boss matched their difficulty and only once you knew how to run the dungeon quickly could you get to the last boss and kill it within the time limit.

The rewards were different for each boss as well...

I'd like to see some dungeons that follow suit in this game.