I would love to have dungeons with branching paths and different ways to complete, but as has been stated in here, the paths would have to either all take roughly the same amount of time to complete or the would have to offer better rewards for taking longer paths. And it would have to be enough of an incentive to warrant spending the extra time. The latter is pretty well impossible because it appears that most of the population only runs the roulettes out of a necessity and they despise every minute they ever spend in a dungeon. So we are left with the former which is to make all paths the same length of time. Maybe one could be more of a series of boss type enemies and another could be more of a horde or swarm of enemies. I would say there could be more puzzles involved but that kind of content is generally disliked by FFXIV players.